title: Joanna Jędrzejczyk

text: Jędrzejczyk made her professional debut in mixed martial arts (MMA) on May 19, 2012, at SFT - MMA Fight Night Diva SPA against Sylwia Juskiewicz, winning via unanimous decision. On December 8, 2012, at MFC 5 she defeated Lily Kazak by submission via rear naked choke. On June 20, 2013, at Battle of Moscow 12 she defeated the then #1 Russian WMMA flyweight fighter Julia Berezikova via unanimous decision.


title: Joanna Jędrzejczyk

text: On June 7, 2014, at Cage Warriors Fighting Championship 69 she defeated Rosi Sexton via knockout in the second round.


title: Joanna Jędrzejczyk

text: Jędrzejczyk officially signed with the Ultimate Fighting Championship (UFC) in July 2014. She made her promotional debut, now fighting as a strawweight, on July 26, 2014, at against Juliana Lima. She won the fight via unanimous decision.


title: Joanna Jędrzejczyk

text: Jędrzejczyk next faced undefeated strawweight top contender Cláudia Gadelha on December 13, 2014, at UFC on Fox 13. She won the fight via split decision. The judges' decision was met with much controversy as the majority of the MMA media scored the bout in favor of Gadelha.


title: Joanna Jędrzejczyk

text: Jędrzejczyk faced Carla Esparza for the UFC Strawweight Championship on March 14, 2015, at UFC 185. Jędrzejczyk won the one-sided bout via TKO in the second round, becoming the first UFC title-holder from Poland and first female European UFC champion. Subsequently, Jędrzejczyk won a "Performance of the Night" bonus.


title: Joanna Jędrzejczyk

text: Jędrzejczyk's first title defense was against Jessica Penne on June 20, 2015, at in Berlin, Germany. She successfully defended the title against Penne, defeating her in the third round via TKO following a flurry of punches and a knee against the cage. Both participants were awarded "Fight of the Night" honors. Jędrzejczyk later underwent surgery to repair a fractured thumb incurred during the fight.


title: Joanna Jędrzejczyk

text: In her second title defense, Jędrzejczyk faced Valérie Létourneau on November 15, 2015, in the co-main event at UFC 193. She won the fight by unanimous decision to retain her title. The 220 significant strikes landed by Jędrzejczyk were the most ever in a championship fight. 70 leg kicks were landed by Jędrzejczyk, the most in UFC history. The previous record was 68, set by Carlos Condit against Nick Diaz at UFC 143.


title: Joanna Jędrzejczyk

text: In early 2016, the UFC announced that Jędrzejczyk would be one of the coaches, opposite former opponent Cláudia Gadelha on . A rematch between the two took place on July 8, 2016, at in the MGM Grand Garden Arena in Las Vegas, Nevada. She won the fight via unanimous decision. Both participants were awarded "Fight of the Night" for their performance.


title: Joanna Jędrzejczyk

text: Jędrzejczyk successfully defended her title for the 4th consecutive time by defeating fellow Pole Karolina Kowalkiewicz by unanimous decision on November 12, 2016, at UFC 205 in Madison Square Garden, the first event the promotion had held in the historic arena.


title: Joanna Jędrzejczyk

text: Jędrzejczyk faced Jéssica Andrade on May 13, 2017, at UFC 211. She won the fight via unanimous decision, and successfully defended her title for the fifth consecutive time. Jędrzejczyk landed the most significant strikes in UFC championship history (225), had the highest significant strike differential in UFC championship history (142), and broke her previous record for most leg kicks thrown in a single fight (75).


title: Joanna Jędrzejczyk

text: For her sixth title defense, Jędrzejczyk faced Rose Namajunas at UFC 217 at Madison Square Garden in New York on November 4, 2017. She lost the bout via KO (punches) in the first round, marking her first professional loss in mixed martial arts competition.


title: Joanna Jędrzejczyk

text: A title fight rematch between Namajunas and Jędrzejczyk took place on April 7, 2018, at UFC 223. She lost the fight via unanimous decision.


title: Joanna Jędrzejczyk

text: On September 20, 2018, it was announced that Jędrzejczyk was expected to return to flyweight to face Valentina Shevchenko on December 8, 2018, at UFC 231 for the vacant UFC Women's Flyweight Championship. Due to UFC 230 being in need of a main event, Shevchenko was booked against Sijara Eubanks. After the UFC announced Cormier vs. Lewis on October 9, 2018, UFC confirmed the bout between Shevchenko and Eubanks was canceled and that Jędrzejczyk would again fight for the title against Shevchenko in the co-main event at UFC 231. Jędrzejczyk lost the fight via a unanimous decision.


title: Joanna Jędrzejczyk

text: Jędrzejczyk faced Michelle Waterson on October 12, 2019, at UFC on ESPN+ 19. Per news reports, Jędrzejczyk had informed the UFC that she might not be able to make the Strawweight limit; however, she weighed in at 115.5 pounds. She won the fight via unanimous decision.


title: Joanna Jędrzejczyk

text: Jędrzejczyk faced Zhang Weili for UFC Women's Strawweight Championship on March 7, 2020, at UFC 248. She lost the fight via split decision. This fight earned her the "Fight of the Night" award, and was considered by many pundits as the greatest fight in women's MMA history.


title: Joanna Jędrzejczyk

text: A rematch between Jędrzejczyk and Zhang took place on June 11, 2022 at UFC 275. Jędrzejczyk lost the fight after getting knocked out with a spinning backfist in the second round. In her post-fight interview, Jędrzejczyk announced her retirement from mixed martial arts, saying, "It's been 20 years. I'm turning 35 this year. I want to be a mom. I want to be a businesswoman. I've been training two decades, more than half of my life. I appreciate you all. I love you guys."


title: Joanna Jędrzejczyk

text: A decorated kickboxer, Jędrzejczyk is known for precise and calculated striking. She employs a sprawl-and-brawl strategy in MMA fighting. While standing with opponents, she constantly varies between high punches and body shots, also utilizing knees, elbows, and high front kicks. She also uses a flurry of strikes just to confuse the opponent before landing a solid strike, much akin to Chuck Liddell. SportsJoe.ie MMA journalist Darragh Murphy summed up her fighting style: "Her technique has the right combination of sublimity and relentlessness, expressing one's typically violent art through beauty, the perfect storm."


title: Joanna Jędrzejczyk

text: Jędrzejczyk is soft-spoken and has a calm and endearing personality with fans. However, she often employs the use of trash-talk against her opponents before fights, and her fights have been known to be violent and bloody. UFC president Dana White has praised her stating "She is so bad ass... pound-for-pound [she is the] best female fighter on Earth... Her killer instinct is ridiculous." MMA media have called Jędrzejczyk "must-see TV".


title: Joanna Jędrzejczyk

text: Jędrzejczyk has been praised for her elite level sprawl-and-brawl strategy. Fightland striking analyst Jack Slack has written that "she's being likened to Chuck Liddell, and that is a pretty solid way to describe her...while she has an undoubtedly better technical striking game than Liddell". BloodyElbow.com striking analyst Connor Ruebusch has written "Distance, angles, and damage. These are the key ingredients of successful takedown defense, and the elements that make Joanna Jędrzejczyk and José Aldo such masterful strikers." "The Washington Post" striking analyst Patrick Wyman wrote that "sound fundamentals fuel the best fighters in the world, and nobody has better mastered the bread and butter of footwork and distance management than Aldo and Jedrzejczyk". Foxsports.com striking analyst Jason Parillo has stated that "Joanna's MMA boxing is remarkable. It's second to none".


title: Joanna Jędrzejczyk

text: Since her training camp for UFC 205, Jędrzejczyk has trained at American Top Team in Coconut Creek, Florida.


title: Joanna Jędrzejczyk

text: Her strength and conditioning coach is Phil Daru. In 2021, Jędrzejczyk was promoted to blue belt in Brazilian jiu-jitsu after training in the gi.


title: Joanna Jędrzejczyk

text: She was the fiancée of former Polish football player Przemysław Buta. In a 2019 interview, she cited "some difficulties" in her personal life for "almost two years," confirming that she is no longer engaged to Buta.


title: Paolo Nutini

text: Paolo Giovanni Nutini (born 9 January 1987) is a Scottish singer, songwriter and musician from Paisley. Nutini's debut album, "These Streets" (2006), peaked at number three on the UK Albums Chart. Its follow-up, "Sunny Side Up" (2009), debuted at number one on the UK Albums Chart. Both albums have been certified quintuple platinum by the British Phonographic Industry. Five years later, Nutini released his third studio album, "Caustic Love", in April 2014. The album received positive reviews from music critics. "Caustic Love" debuted at number one on the UK Album Charts and was certified platinum by the BPI in June 2014. While Nutini has not formally addressed it, he was on a hiatus from 2017 to May 2022, when he announced his fourth album, "Last Night in the Bittersweet".


title: Paolo Nutini

text: Among other accolades, Nutini has received three BRIT Award nominations and an Ivor Novello Award nomination for songwriting. In July 2014, he was referred to by the BBC as "arguably Scotland's biggest musician right now."


title: Paolo Nutini

text: Nutini was born in Paisley, Scotland, and has a younger sister. His father, Alfredo, is a Scot of Italian descent from Barga in Tuscany, while his mother, Linda, is Scottish. He was expected to follow his father into the family fish and chip shop business. As a child he attended PACE Youth Theatre. He was first encouraged to sing by his music-loving grandfather, Giovanni "Jackie" Nutini, and a teacher at his school, St Andrews Academy, who recognised his talent.


title: Paolo Nutini

text: Nutini left school to work as a roadie and to sell t-shirts for Scottish band Speedway. He spent three years learning the music business and performing live. He later worked as a studio hand at Glasgow's Park Lane Studio. It was here where he started demo-ing songs, writing with Jim Duguid and the drummer of Speedway.


title: Paolo Nutini

text: His big chance came when his younger family member signed him up to his first live show 102.5 Clyde 1 for David Sneddon's return to his home town of Paisley at the beginning of 2003. Sneddon was delayed, and as the winner of an impromptu pop quiz, Nutini was given the chance to perform a couple of songs on stage during the wait. The favourable reaction of the crowd impressed another member of the audience, Brendan Moon, who offered to become his manager with his business partner, Mike Bawden. Mike Bawden continues to manage Nutini.


title: Paolo Nutini

text: At 17, Nutini moved to London and performed regularly at The Bedford pub in Balham with local Singer-Songwriter Charlie Wallis. Other radio and live appearances followed, including two live acoustic spots on Radio London, The Hard Rock Cafe, and support slots for The Rolling Stones, Amy Winehouse and KT Tunstall. Nutini became known for singing with his eyes closed during his entire performances.


title: Paolo Nutini

text: Nutini made his first demo which saw him signed to Atlantic Records in May 2005, shortly after his 18th birthday. He released his first single "These Streets" as a free download in May 2006; this was then followed by his next single "Last Request" which was released on 4 July 2006 and charted at number five on the UK Singles Chart.


title: Paolo Nutini

text: In the video for "Last Request", Nutini plays the part of a robber – though this is not revealed until the end.


title: Paolo Nutini

text: Nutini's third single, "Jenny Don't Be Hasty", was released on 25 September 2006 and got to number twenty on the UK Singles Chart. "Rewind" was Nutini's fourth single. It was released on 4 December 2006, and reached number twenty seven on the UK Singles Chart.


title: Paolo Nutini

text: Nutini's debut album "These Streets", produced by Ken Nelson (who has also worked with Coldplay and Gomez), was released on 17 July 2006 and immediately entered the UK album charts at number three. Many of the songs on the album, including "Last Request" and "Rewind", were inspired by a turbulent relationship with his former girlfriend Teri Brogan, and "Jenny Don't Be Hasty" is a true story about encounters with an older woman.


title: Paolo Nutini

text: Commenting on "These Streets", Nutini himself states on his official website, "The album is a little glimpse of some of the experiences I have been through in the last three years". In late 2007, Nutini covered Labi Siffre's "It Must Be Love" for BBC Radio 1's "Radio 1 Established 1967" album.


title: Paolo Nutini

text: Throughout 2006, Nutini played a number of sold-out concerts across Britain and performed at a wide variety of venues worldwide, including King Tut's Wah Wah Hut in Glasgow, a TV appearance on Later with Jools Holland, Carnegie Hall in New York, The Montreux Jazz Festival, The Wireless Festival, Oxegen and T in the Park. He supported the Rolling Stones in Vienna and was invited to appear with them again at the Don Valley Stadium in August 2006 and was also booked to appear at the V Festival and The Austin City Limits Music Festival, Texas, later in 2006, with a European tour in the autumn. In May 2006, Nutini also played at BBC Radio 1's Big Weekend in Dundee.


title: Paolo Nutini

text: Nutini performed at the Glastonbury Festival in June 2007 on the famous Pyramid Stage on the second day of the event. Nutini also performed at the British leg of Live Earth at Wembley Stadium on 7 July 2007, with his set including a cover of "What A Wonderful World", a classic pop tune by Bob Thiele, George David Weiss, and George Douglas. He performed the following day at T in the Park, in Scotland. He performed at the Ahmet Ertegun Tribute Concert on 10 December 2007, an event that drew enormous international attention as it was the first full live concert performance by Led Zeppelin in 27 years. Scottish independent TV company Volt MediaFix made a one-off documentary of Nutini's US tour. The programme, for the BBC, was scheduled for broadcast on BBC2, on Thursday 7 June throughout Scotland and on Sky channel 990 throughout the rest of Britain.


title: Paolo Nutini

text: On 1 June 2009, Nutini released his second studio album "Sunny Side Up", which debuted at number one. The first single from the album, "Candy", was released on 25 May. In July, he appeared on "Friday Night with Jonathan Ross", performing "Coming Up Easy". This was released as the second single to the album on 10 August and it debuted at number 62 in the UK Singles Chart on 16 August 2009. On 10 September 2009, Nutini performed "Coming Up Easy" on The Tonight Show with Conan O'Brien. The third single from the album was "Pencil Full of Lead".


title: Paolo Nutini

text: The album received a mixed critical reception. Some noted the move away from the sound of the debut album. Neil McCormick of "The Daily Telegraph" was also positive, stating "his joyous second album organically blends soul, country, folk and the brash, horny energy of ragtime swing." Some reviewers were less impressed. It was described by "The Guardian"'s Caroline Sullivan as "not bad", with opening track "10/10" described as "jaunty enough to make you retch".


title: Paolo Nutini

text: The album debuted at number one on the UK Albums Chart with sales of over 60,000 copies, fighting off strong competition from "Love & War", the debut album of fellow male solo artist Daniel Merriweather. The album performed similarly well on the Irish Albums Chart, debuting at number two behind Eminem's new album before rising to the top of the charts the week after. The album has been one of the best UK album sales of the year. On the UK Albums Chart on the week of Monday 19 October, the album went from number 31 to number 5, making the album sell more than The Saturdays' second album. On 3 January 2010 "Sunny Side Up" topped the UK Album Charts for a second time, making the album the first Number one album in the United Kingdom of 2010 and the decade.


title: Paolo Nutini

text: In December 2013, it was revealed that Nutini had recorded a third album called "Caustic Love", which was released on 14 April 2014. The album's first single "Scream (Funk My Life Up)" was released on 27 January. "The Independent" newspaper described the album as, "an unqualified success: "Caustic Love" may be the best UK R&B album since the 1970s blue-eyed-soul heyday of Rod Stewart and Joe Cocker". It was selected on 8 December 2014 by Apple to become the Best Album in iTunes' 'Best of 2014'. An 18-month tour following the release of "Caustic Love" saw Nutini perform in North America, Europe, South Africa, Australia and New Zealand. In October 2014 Nutini was forced to pull out of shows in his hometown of Glasgow, Cardiff and London due to tonsillitis.


title: Paolo Nutini

text: After extensive touring in 2015 in support of "Caustic Love", Nutini took a hiatus in 2016 although he performed an emotional tribute in memory of a Welsh fan in Newport, Wales on 20 July. On 20 September 2016 it was announced that Nutini would headline the Concert in the Gardens, the flagship event of Edinburgh's Hogmanay street party, on New Year's Eve 2016/2017. Tickets were sold out in a record-breaking three hours leading to an unprecedented second show (named "The Night Afore") being announced for 30 December.


title: Paolo Nutini

text: Over eight years following the release of "Caustic Love", Nutini announced on 11 May 2022 that his fourth studio album, "Last Night in the Bittersweet", would be released on 1 July 2022. Alongside the announcement, he released two songs from the album, titled "Through the Echoes" and "Lose It". On 8 July 2022, he headlined TRNSMT festival.


title: Paolo Nutini

text: On Hogmanay 2006, Nutini appeared on BBC Scotland's Hogmanay Live celebrations after the official celebrations in Princes Street Gardens were cancelled at short notice due to abysmal weather. He performed several songs in the Great Hall of Edinburgh Castle for the TV audience with little or no rehearsal. On Wednesday 11 April 2007, Nutini performed in a concert that was streamed live via MSN Music.


title: Paolo Nutini

text: Nutini's songs have infiltrated American TV shows as well. "Last Request" featured at the end of the "Scrubs" episode "My Words of Wisdom" from Season 6, the first-ever episode of "Gavin & Stacey" and the "One Tree Hill" Season-4 episode "The Birth and Death of the Day." "Million Faces" could be heard at the end of the "Grey's Anatomy" episode "Testing 1–2–3" from Season 3 and is on the Volume 3 Soundtrack. "Rewind" was played at the end of "" Season-5 episode "Broken Home." "Jenny, Don't Be Hasty" was also featured on another member of the "CSI" franchise when it played on ""'s Season-3-finale, "". "New Shoes" featured in "The Jane Austen Book Club" and in a TV ad for Puma AG during summer 2008. "One Day" from the Caustic Love album was featured near the end of NBC's "State of Affairs" Season 1 Episode 7 in January 2014. "Iron Sky" was played in "Elementary" Season-3 episode "End of Watch."


title: Paolo Nutini

text: On 24 July 2007, Nutini was awarded The Golden St Christopher medal by the city of Barga in Italy, the highest honour the city can give, to celebrate his extraordinary contributions to Barga and its people. On 18 September, Nutini performed "Last Request" on "The Tonight Show with Jay Leno". In September 2007, Nutini recorded a short radio show with imeem.com where he listed his top 10 favourite tracks and the reasons behind his choices. In October 2007, Nutini performed for the annual Voodoo Fest held in New Orleans, Louisiana. In 2008, Nutini's music was featured in a movie adaptation of Irvine Welsh's best-selling novel "".


title: Paolo Nutini

text: On New Year's Eve 2008–09, Nutini performed at the Hogmanay street parties in both Edinburgh and Glasgow, Scotland, becoming the first act to play both locations on the same day for the event. In The View's 2009 album "Which Bitch?", he is featured singing on the song "Covers." Nutini appeared in the 2011 documentary "Reggae Got Soul: The Story of Toots and the Maytals" which was featured on BBC and described as "The untold story of one of the most influential artists ever to come out of Jamaica".


title: Paolo Nutini

text: On 27 July 2012, Nutini sang at the London 2012 Olympic Games Opening Ceremony Concert in London's Hyde Park, along with Duran Duran, Snow Patrol and Stereophonics.


title: Paolo Nutini

text: Nutini had an 8-year on-again, off-again relationship with Scottish marketing graduate and model Teri Brogan. The pair met at St Andrew's Academy in Paisley and started dating when they were 15. After their split, he was romantically involved with Irish TV presenter and model Laura Whitmore. Nutini had a relationship with English actress and model Amber Anderson from 2014 until 2016.


title: Paolo Nutini

text: Nutini stated in a June 2014 interview that he has smoked cannabis every day of his life since the age of sixteen. Nutini also has an Honorary Doctorate from his hometown university in Paisley, the University of the West of Scotland.


title: Paolo Nutini

text: On 22 February 2015, a biography about Nutini was published under the title "Paolo Nutini: Coming Up Easy". The biography was written by the author Colin MacFarlane.


title: Paolo Nutini

text: In July 2019, Paolo donated over £10,000 to the charity Tiny Changes by buying and raffling off the Chewbacca mask worn on stage by fellow Scottish musician Lewis Capaldi at TRNSMT.


title: Microphone

text: A microphone, colloquially called a mic or mike (), is a transducer that converts sound into an electrical signal. Microphones are used in many applications such as telephones, hearing aids, public address systems for concert halls and public events, motion picture production, live and recorded audio engineering, sound recording, two-way radios, megaphones, and radio and television broadcasting. They are also used in computers for recording voice, speech recognition, VoIP, and for other purposes such as ultrasonic sensors or knock sensors.


title: Microphone

text: Several types of microphone are used today, which employ different methods to convert the air pressure variations of a sound wave to an electrical signal. The most common are the dynamic microphone, which uses a coil of wire suspended in a magnetic field; the condenser microphone, which uses the vibrating diaphragm as a capacitor plate; and the contact microphone, which uses a crystal of piezoelectric material. Microphones typically need to be connected to a preamplifier before the signal can be recorded or reproduced.


title: Microphone

text: In order to speak to larger groups of people, a need arose to increase the volume of the human voice. The earliest devices used to achieve this were acoustic megaphones. Some of the first examples, from fifth-century-BC Greece, were theater masks with horn-shaped mouth openings that acoustically amplified the voice of actors in amphitheaters. In 1665, the English physicist Robert Hooke was the first to experiment with a medium other than air with the invention of the "lovers' telephone" made of stretched wire with a cup attached at each end.


title: Microphone

text: In 1856, Antonio Meucci invented a dynamic microphone based on the generation of electric current by moving a coil of wire to various depths in a magnetic field. This method of modulation was also the most enduring method for the technology of the telephone as well. Speaking of his device, Meucci wrote in 1857, “It consists of a vibrating diaphragm and an electrified magnet with a spiral wire that wraps around it. The vibrating diaphragm alters the current of the magnet. These alterations of current, transmitted to the other end of the wire, create analogous vibrations of the receiving diaphragm and reproduce the word.”


title: Microphone

text: In 1861, German inventor Johann Philipp Reis built an early sound transmitter (the "Reis telephone") that used a metallic strip attached to a vibrating membrane that would produce intermittent current. Better results were achieved in 1876 with the "liquid transmitter" design in early telephones from Alexander Graham Bell and Elisha Gray – the diaphragm was attached to a conductive rod in an acid solution. These systems, however, gave a very poor sound quality.


title: Microphone

text: The first microphone that enabled proper voice telephony was the (loose-contact) carbon microphone. This was independently developed by David Edward Hughes in England and Emile Berliner and Thomas Edison in the US. Although Edison was awarded the first patent (after a long legal dispute) in mid-1877, Hughes had demonstrated his working device in front of many witnesses some years earlier, and most historians credit him with its invention. The Berliner microphone found commercial success through the use by Alexander Graham Bell for his telephone and Berliner became employed by Bell. The carbon microphone is the direct prototype of today's microphones and was critical in the development of telephony, broadcasting and the recording industries. Thomas Edison refined the carbon microphone into his carbon-button transmitter of 1886. This microphone was employed at the first radio broadcast ever, a performance at the New York Metropolitan Opera House in 1910.


title: Microphone

text: In 1916, E.C. Wente of Western Electric developed the next breakthrough with the first condenser microphone. In 1923, the first practical moving coil microphone was built. The Marconi-Sykes magnetophone, developed by Captain H. J. Round, became the standard for BBC studios in London. This was improved in 1930 by Alan Blumlein and Herbert Holman who released the HB1A and was the best standard of the day.


title: Microphone

text: Also in 1923, the ribbon microphone was introduced, another electromagnetic type, believed to have been developed by Harry F. Olson, who essentially reverse-engineered a ribbon speaker. Over the years these microphones were developed by several companies, most notably RCA that made large advancements in pattern control, to give the microphone directionality. With television and film technology booming there was a demand for high-fidelity microphones and greater directionality. Electro-Voice responded with their Academy Award-winning shotgun microphone in 1963.


title: Microphone

text: During the second half of the 20th century, development advanced quickly with the Shure Brothers bringing out the SM58 and SM57. The latest research developments include the use of fibre optics, lasers and interferometers.


title: Microphone

text: The sensitive transducer element of a microphone is called its "element" or "capsule." Sound is first converted to mechanical motion by means of a diaphragm, the motion of which is then converted to an electrical signal. A complete microphone also includes a housing, some means of bringing the signal from the element to other equipment, and often an electronic circuit to adapt the output of the capsule to the equipment being driven. A wireless microphone contains a radio transmitter.


title: Microphone

text: Microphones are categorized by their transducer principle, such as condenser, dynamic, etc., and by their directional characteristics. Sometimes other characteristics such as diaphragm size, intended use or orientation of the principal sound input to the principal axis (end- or side-address) of the microphone are used to describe the microphone.


title: Microphone

text: The condenser microphone, invented at Western Electric in 1916 by E. C. Wente, is also called a capacitor microphone or electrostatic microphone—capacitors were historically called condensers. The diaphragm acts as one plate of a capacitor, and audio vibrations produce changes in the distance between the plates. Because the capacitance of the plates is inversely proportional to the distance between them, the vibrations produce changes in capacitance. These changes in capacitance are used to measure the audio signal. The assembly of fixed and movable plates is called an "element" or "capsule".


title: Microphone

text: Condenser microphones span the range from telephone transmitters through inexpensive karaoke microphones to high-fidelity recording microphones. They generally produce a high-quality audio signal and are now the popular choice in laboratory and recording studio applications. The inherent suitability of this technology is due to the very small mass that must be moved by the incident sound wave, unlike other microphone types that require the sound wave to do more work.


title: Microphone

text: Condenser microphones require a power source, provided either via microphone inputs on equipment as phantom power or from a small battery. Power is necessary for establishing the capacitor plate voltage and is also needed to power the microphone electronics (impedance conversion in the case of electret and DC-polarized microphones, demodulation or detection in the case of RF/HF microphones). Condenser microphones are also available with two diaphragms that can be electrically connected to provide a range of polar patterns (see below), such as cardioid, omnidirectional, and figure-eight. It is also possible to vary the pattern continuously with some microphones, for example, the Røde NT2000 or CAD M179.


title: Microphone

text: There are two main categories of condenser microphones, depending on the method of extracting the audio signal from the transducer: DC-biased microphones, and radio frequency (RF) or high frequency (HF) condenser microphones.


title: Microphone

text: With a DC-biased condenser microphone, the plates are biased with a fixed charge ("Q"). The voltage maintained across the capacitor plates changes with the vibrations in the air, according to the capacitance equation (C = ), where Q = charge in coulombs, C = capacitance in farads and V = potential difference in volts. A nearly constant charge is maintained on the capacitor. As the capacitance changes, the charge across the capacitor does change very slightly, but at audible frequencies it is sensibly constant. The capacitance of the capsule (around 5 to 100 pF) and the value of the bias resistor (100 MΩ to tens of GΩ) form a filter that is high-pass for the audio signal, and low-pass for the bias voltage. Note that the time constant of an RC circuit equals the product of the resistance and capacitance.


title: Microphone

text: Within the time-frame of the capacitance change (as much as 50 ms at 20 Hz audio signal), the charge is practically constant and the voltage across the capacitor changes instantaneously to reflect the change in capacitance. The voltage across the capacitor varies above and below the bias voltage. The voltage difference between the bias and the capacitor is seen across the series resistor. The voltage across the resistor is amplified for performance or recording. In most cases, the electronics in the microphone itself contribute no voltage gain as the voltage differential is quite significant, up to several volts for high sound levels. Since this is a very high impedance circuit, only current gain is usually needed, with the voltage remaining constant.


title: Microphone

text: RF condenser microphones use a comparatively low RF voltage, generated by a low-noise oscillator. The signal from the oscillator may either be amplitude modulated by the capacitance changes produced by the sound waves moving the capsule diaphragm, or the capsule may be part of a resonant circuit that modulates the frequency of the oscillator signal. Demodulation yields a low-noise audio frequency signal with a very low source impedance. The absence of a high bias voltage permits the use of a diaphragm with looser tension, which may be used to achieve wider frequency response due to higher compliance. The RF biasing process results in a lower electrical impedance capsule, a useful by-product of which is that RF condenser microphones can be operated in damp weather conditions that could create problems in DC-biased microphones with contaminated insulating surfaces. The Sennheiser "MKH" series of microphones use the RF biasing technique. A covert, remotely energised application of the same physical principle was devised by Soviet Russian inventor Leon Theremin and used to bug the US Ambassador's Residence in Moscow between 1945 and 1952.


title: Microphone

text: An electret microphone is a type of condenser microphone invented by Gerhard Sessler and Jim West at Bell laboratories in 1962.


title: Microphone

text: The externally applied charge used for a conventional condenser microphone is replaced by a permanent charge in an electret material. An electret is a ferroelectric material that has been permanently electrically charged or "polarized". The name comes from "electr"ostatic and magn"et"; a static charge is embedded in an electret by the alignment of the static charges in the material, much the way a permanent magnet is made by aligning the magnetic domains in a piece of iron.


title: Microphone

text: Due to their good performance and ease of manufacture, hence low cost, the vast majority of microphones made today are electret microphones; a semiconductor manufacturer estimates annual production at over one billion units. They are used in many applications, from high-quality recording and lavalier (lapel mic) use to built-in microphones in small sound recording devices and telephones. Prior to the proliferation of MEMS microphones, nearly all cell-phone, computer, PDA and headset microphones were electret types.


title: Microphone

text: Unlike other capacitor microphones, they require no polarizing voltage, but often contain an integrated preamplifier that does require power (often incorrectly called polarizing power or bias). This preamplifier is frequently phantom powered in sound reinforcement and studio applications. Monophonic microphones designed for personal computers (PCs), sometimes called multimedia microphones, use a 3.5 mm plug as usually used, without power, for stereo; the ring, instead of carrying the signal for a second channel, carries power via a resistor from (normally) a 5 V supply in the computer. Stereophonic microphones use the same connector; there is no obvious way to determine which standard is used by equipment and microphones.


title: Microphone

text: Though electret microphones were once considered low quality, the best ones can now rival traditional condenser microphones in every respect and can even offer the long-term stability and ultra-flat response needed for a measurement microphone. Only the best electret microphones rival good DC-polarized units in terms of noise level and quality; electret microphones lend themselves to inexpensive mass-production, while inherently expensive non-electret condenser microphones are made to higher quality.


title: Microphone

text: A valve microphone is a condenser microphone that uses a vacuum tube (valve) amplifier. They remain popular with enthusiasts of tube sound.


title: Microphone

text: The dynamic microphone (also known as the moving-coil microphone) works via electromagnetic induction. They are robust, relatively inexpensive and resistant to moisture. This, coupled with their potentially high gain before feedback, makes them ideal for on-stage use.


title: Microphone

text: Dynamic microphones use the same dynamic principle as in a loudspeaker, only reversed. A small movable induction coil, positioned in the magnetic field of a permanent magnet, is attached to the diaphragm. When sound enters through the windscreen of the microphone, the sound wave moves the diaphragm. When the diaphragm vibrates, the coil moves in the magnetic field, producing a varying current in the coil through electromagnetic induction. A single dynamic membrane does not respond linearly to all audio frequencies. For this reason, some microphones utilize multiple membranes for the different parts of the audio spectrum and then combine the resulting signals. Combining the multiple signals correctly is difficult; designs that do this are rare and tend to be expensive. On the other hand, there are several designs that are more specifically aimed towards isolated parts of the audio spectrum. The AKG D112, for example, is designed for bass response rather than treble. In audio engineering several kinds of microphones are often used at the same time to get the best results.


title: Microphone

text: Ribbon microphones use a thin, usually corrugated metal ribbon suspended in a magnetic field. The ribbon is electrically connected to the microphone's output, and its vibration within the magnetic field generates the electrical signal. Ribbon microphones are similar to moving coil microphones in the sense that both produce sound by means of magnetic induction. Basic ribbon microphones detect sound in a bi-directional (also called figure-eight, as in the diagram below) pattern because the ribbon is open on both sides. Also, because the ribbon has much less mass it responds to the air velocity rather than the sound pressure. Though the symmetrical front and rear pickup can be a nuisance in normal stereo recording, the high side rejection can be used to advantage by positioning a ribbon microphone horizontally, for example above cymbals, so that the rear lobe picks up sound only from the cymbals. Crossed figure 8, or Blumlein pair, stereo recording is gaining in popularity, and the figure-eight response of a ribbon microphone is ideal for that application.


title: Microphone

text: Other directional patterns are produced by enclosing one side of the ribbon in an acoustic trap or baffle, allowing sound to reach only one side. The classic RCA Type 77-DX microphone has several externally adjustable positions of the internal baffle, allowing the selection of several response patterns ranging from "figure-eight" to "unidirectional". Such older ribbon microphones, some of which still provide high-quality sound reproduction, were once valued for this reason, but a good low-frequency response could be obtained only when the ribbon was suspended very loosely, which made them relatively fragile. Modern ribbon materials, including new nanomaterials, have now been introduced that eliminate those concerns and even improve the effective dynamic range of ribbon microphones at low frequencies. Protective wind screens can reduce the danger of damaging a vintage ribbon, and also reduce plosive artifacts in the recording. Properly designed wind screens produce negligible treble attenuation. In common with other classes of dynamic microphone, ribbon microphones don't require phantom power; in fact, this voltage can damage some older ribbon microphones. Some new modern ribbon microphone designs incorporate a preamplifier and, therefore, do require phantom power, and circuits of modern passive ribbon microphones, "i.e.", those without the aforementioned preamplifier, are specifically designed to resist damage to the ribbon and transformer by phantom power. Also there are new ribbon materials available that are immune to wind blasts and phantom power.


title: Microphone

text: The carbon microphone was the earliest type of microphone. The carbon button microphone (or sometimes just a button microphone), uses a capsule or button containing carbon granules pressed between two metal plates like the Berliner and Edison microphones. A voltage is applied across the metal plates, causing a small current to flow through the carbon. One of the plates, the diaphragm, vibrates in sympathy with incident sound waves, applying a varying pressure to the carbon. The changing pressure deforms the granules, causing the contact area between each pair of adjacent granules to change, and this causes the electrical resistance of the mass of granules to change. The changes in resistance cause a corresponding change in the current flowing through the microphone, producing the electrical signal. Carbon microphones were once commonly used in telephones; they have extremely low-quality sound reproduction and a very limited frequency response range but are very robust devices. The Boudet microphone, which used relatively large carbon balls, was similar to the granule carbon button microphones.


title: Microphone

text: Unlike other microphone types, the carbon microphone can also be used as a type of amplifier, using a small amount of sound energy to control a larger amount of electrical energy. Carbon microphones found use as early telephone repeaters, making long-distance phone calls possible in the era before vacuum tubes. Called a Brown's relay, these repeaters worked by mechanically coupling a magnetic telephone receiver to a carbon microphone: the faint signal from the receiver was transferred to the microphone, where it modulated a stronger electric current, producing a stronger electrical signal to send down the line. One illustration of this amplifier effect was the oscillation caused by feedback, resulting in an audible squeal from the old "candlestick" telephone if its earphone was placed near the carbon microphone.


title: Microphone

text: A crystal microphone or piezo microphone uses the phenomenon of piezoelectricity—the ability of some materials to produce a voltage when subjected to pressure—to convert vibrations into an electrical signal. An example of this is potassium sodium tartrate, which is a piezoelectric crystal that works as a transducer, both as a microphone and as a slimline loudspeaker component. Crystal microphones were once commonly supplied with vacuum tube (valve) equipment, such as domestic tape recorders. Their high output impedance matched the high input impedance (typically about 10 megohms) of the vacuum tube input stage well. They were difficult to match to early transistor equipment and were quickly supplanted by dynamic microphones for a time, and later small electret condenser devices. The high impedance of the crystal microphone made it very susceptible to handling noise, both from the microphone itself and from the connecting cable.


title: Microphone

text: Piezoelectric transducers are often used as contact microphones to amplify sound from acoustic musical instruments, to sense drum hits, for triggering electronic samples, and to record sound in challenging environments, such as underwater under high pressure. Saddle-mounted pickups on acoustic guitars are generally piezoelectric devices that contact the strings passing over the saddle. This type of microphone is different from magnetic coil pickups commonly visible on typical electric guitars, which use magnetic induction, rather than mechanical coupling, to pick up vibration.


title: Microphone

text: A fiber-optic microphone converts acoustic waves into electrical signals by sensing changes in light intensity, instead of sensing changes in capacitance or magnetic fields as with conventional microphones.


title: Microphone

text: During operation, light from a laser source travels through an optical fiber to illuminate the surface of a reflective diaphragm. Sound vibrations of the diaphragm modulate the intensity of light reflecting off the diaphragm in a specific direction. The modulated light is then transmitted over a second optical fiber to a photodetector, which transforms the intensity-modulated light into analog or digital audio for transmission or recording. Fiber-optic microphones possess high dynamic and frequency range, similar to the best high fidelity conventional microphones.


title: Microphone

text: Fiber-optic microphones do not react to or influence any electrical, magnetic, electrostatic or radioactive fields (this is called EMI/RFI immunity). The fiber-optic microphone design is therefore ideal for use in areas where conventional microphones are ineffective or dangerous, such as inside industrial turbines or in magnetic resonance imaging (MRI) equipment environments.


title: Microphone

text: Fiber-optic microphones are robust, resistant to environmental changes in heat and moisture, and can be produced for any directionality or impedance matching. The distance between the microphone's light source and its photodetector may be up to several kilometers without need for any preamplifier or another electrical device, making fiber-optic microphones suitable for industrial and surveillance acoustic monitoring.


title: Microphone

text: Fiber-optic microphones are used in very specific application areas such as for infrasound monitoring and noise-canceling. They have proven especially useful in medical applications, such as allowing radiologists, staff and patients within the powerful and noisy magnetic field to converse normally, inside the MRI suites as well as in remote control rooms. Other uses include industrial equipment monitoring and audio calibration and measurement, high-fidelity recording and law enforcement.


title: Microphone

text: Laser microphones are often portrayed in movies as spy gadgets because they can be used to pick up sound at a distance from the microphone equipment. A laser beam is aimed at the surface of a window or other plane surface that is affected by sound. The vibrations of this surface change the angle at which the beam is reflected, and the motion of the laser spot from the returning beam is detected and converted to an audio signal.


title: Microphone

text: In a more robust and expensive implementation, the returned light is split and fed to an interferometer, which detects movement of the surface by changes in the optical path length of the reflected beam. The former implementation is a tabletop experiment; the latter requires an extremely stable laser and precise optics.


title: Microphone

text: A new type of laser microphone is a device that uses a laser beam and smoke or vapor to detect sound vibrations in free air. On 25 August 2009, U.S. patent 7,580,533 issued for a Particulate Flow Detection Microphone based on a laser-photocell pair with a moving stream of smoke or vapor in the laser beam's path. Sound pressure waves cause disturbances in the smoke that in turn cause variations in the amount of laser light reaching the photodetector. A prototype of the device was demonstrated at the 127th Audio Engineering Society convention in New York City from 9 through 12 October 2009.


title: Microphone

text: Early microphones did not produce intelligible speech, until Alexander Graham Bell made improvements including a variable-resistance microphone/transmitter. Bell's liquid transmitter consisted of a metal cup filled with water with a small amount of sulfuric acid added. A sound wave caused the diaphragm to move, forcing a needle to move up and down in the water. The electrical resistance between the wire and the cup was then inversely proportional to the size of the water meniscus around the submerged needle. Elisha Gray filed a caveat for a version using a brass rod instead of the needle. Other minor variations and improvements were made to the liquid microphone by Majoranna, Chambers, Vanni, Sykes, and Elisha Gray, and one version was patented by Reginald Fessenden in 1903. These were the first working microphones, but they were not practical for commercial application. The famous first phone conversation between Bell and Watson took place using a liquid microphone.


title: Microphone

text: The MEMS (microelectromechanical systems) microphone is also called a microphone chip or silicon microphone. A pressure-sensitive diaphragm is etched directly into a silicon wafer by MEMS processing techniques and is usually accompanied with an integrated preamplifier. Most MEMS microphones are variants of the condenser microphone design. Digital MEMS microphones have built-in analog-to-digital converter (ADC) circuits on the same CMOS chip making the chip a digital microphone and so more readily integrated with modern digital products. Major manufacturers producing MEMS silicon microphones are Wolfson Microelectronics (WM7xxx) now Cirrus Logic, InvenSense (product line sold by Analog Devices), Akustica (AKU200x), Infineon (SMM310 product), Knowles Electronics, Memstech (MSMx), NXP Semiconductors (division bought by Knowles), Sonion MEMS, Vesper, AAC Acoustic Technologies, and Omron.


title: Microphone

text: More recently, since the 2010s, there has been increased interest and research into making piezoelectric MEMS microphones which are a significant architectural and material change from existing condenser style MEMS designs.


title: Microphone

text: In a plasma microphone a plasma arc of ionised gas is used. The sound waves cause variations in the pressure around the plasma in turn causing variations in temperature which alter the conductance of the plasma. These variations in conductance can be picked up as variations superimposed on the electrical supply to the plasma. This is a very rare form of microphone.


title: Microphone

text: A loudspeaker, a transducer that turns an electrical signal into sound waves, is the functional opposite of a microphone. Since a conventional speaker is similar in construction to a dynamic microphone (with a diaphragm, coil and magnet), speakers can actually work "in reverse" as microphones. Reciprocity applies, so the resulting microphone has the same impairments as a single-driver loudspeaker: limited low- and high-end frequency response, poorly controlled directivity, and low sensitivity. In practical use, speakers are sometimes used as microphones in applications where high bandwidth and sensitivity are not needed such as intercoms, walkie-talkies or video game voice chat peripherals, or when conventional microphones are in short supply.


title: Microphone

text: However, there is at least one practical application that exploits those weaknesses: the use of a medium-size woofer placed closely in front of a "kick drum" (bass drum) in a drum set to act as a microphone. A commercial product example is the Yamaha Subkick, a woofer shock-mounted into a 10" drum shell used in front of kick drums. Since a relatively massive membrane is unable to transduce high frequencies while being capable of tolerating strong low-frequency transients, the speaker is often ideal for picking up the kick drum while reducing bleed from the nearby cymbals and snare drums.


title: Microphone

text: Less commonly, microphones themselves can be used as speakers, but due to their low power handling and small transducer sizes, a tweeter is the most practical application. One instance of such an application was the STC microphone-derived 4001 super-tweeter, which was successfully used in a number of high-quality loudspeaker systems from the late 1960s to the mid-70s.


title: Microphone

text: The inner elements of a microphone are the primary source of differences in directivity. A pressure microphone uses a diaphragm between a fixed internal volume of air and the environment and responds uniformly to pressure from all directions, so it is said to be omnidirectional. A pressure-gradient microphone uses a diaphragm that is at least partially open on both sides. The pressure difference between the two sides produces its directional characteristics. Other elements such as the external shape of the microphone and external devices such as interference tubes can also alter a microphone's directional response. A pure pressure-gradient microphone is equally sensitive to sounds arriving from front or back but insensitive to sounds arriving from the side because sound arriving at the front and back at the same time creates no gradient between the two. The characteristic directional pattern of a pure pressure-gradient microphone is like a figure-8. Other polar patterns are derived by creating a capsule that combines these two effects in different ways. The cardioid, for instance, features a partially closed backside, so its response is a combination of pressure and pressure-gradient characteristics.


title: Microphone

text: <gallery widths="150" heights="150" mode="packed" caption="Microphone polar sensitivity. Microphone is parallel to the page facing upwards in each diagram.<ref></ref>">


title: Microphone

text: A microphone's directionality or polar pattern indicates how sensitive it is to sounds arriving at different angles about its central axis. The polar patterns illustrated above represent the locus of points that produce the same signal level output in the microphone if a given sound pressure level (SPL) is generated from that point. How the physical body of the microphone is oriented relative to the diagrams depends on the microphone design. For large-membrane microphones such as in the Oktava (pictured above), the upward direction in the polar diagram is usually perpendicular to the microphone body, commonly known as "side fire" or "side address". For small diaphragm microphones such as the Shure (also pictured above), it usually extends from the axis of the microphone commonly known as "end fire" or "top/end address".


title: Microphone

text: Some microphone designs combine several principles in creating the desired polar pattern. This ranges from shielding (meaning diffraction/dissipation/absorption) by the housing itself to electronically combining dual membranes.


title: Microphone

text: An omnidirectional (or nondirectional) microphone's response is generally considered to be a perfect sphere in three dimensions. In the real world, this is not the case. As with directional microphones, the polar pattern for an "omnidirectional" microphone is a function of frequency. The body of the microphone is not infinitely small and, as a consequence, it tends to get in its own way with respect to sounds arriving from the rear, causing a slight flattening of the polar response. This flattening increases as the diameter of the microphone (assuming it's cylindrical) reaches the wavelength of the frequency in question. Therefore, the smallest diameter microphone gives the best omnidirectional characteristics at high frequencies.


title: Microphone

text: The wavelength of sound at 10 kHz is 1.4" (3.5 cm). The smallest measuring microphones are often 1/4" (6 mm) in diameter, which practically eliminates directionality even up to the highest frequencies. Omnidirectional microphones, unlike cardioids, do not employ resonant cavities as delays, and so can be considered the "purest" microphones in terms of low coloration; they add very little to the original sound. Being pressure-sensitive they can also have a very flat low-frequency response down to 20 Hz or below. Pressure-sensitive microphones also respond much less to wind noise and plosives than directional (velocity sensitive) microphones.


title: Microphone

text: A unidirectional microphone is primarily sensitive to sounds from only one direction. The diagram above (shotgun) illustrates a number of these patterns. The microphone faces upwards in each diagram. The sound intensity for a particular frequency is plotted for angles radially from 0 to 360°. (Professional diagrams show these scales and include multiple plots at different frequencies. The diagrams given here provide only an overview of typical pattern shapes, and their names.)


title: Microphone

text: The most common unidirectional microphone is a cardioid microphone, so named because the sensitivity pattern is "heart-shaped", i.e. a cardioid. The cardioid family of microphones are commonly used as vocal or speech microphones since they are good at rejecting sounds from other directions. In three dimensions, the cardioid is shaped like an apple centred around the microphone, which is the "stem" of the apple. The cardioid response reduces pickup from the side and rear, helping to avoid feedback from the monitors. Since these directional transducer microphones achieve their patterns by sensing pressure gradient, putting them very close to the sound source (at distances of a few centimeters) results in a bass boost due to the increased gradient. This is known as the proximity effect. The SM58 has been the most commonly used microphone for live vocals for more than 50 years demonstrating the importance and popularity of cardioid mics.


title: Microphone

text: The cardioid is effectively a superposition of an omnidirectional (pressure) and a figure-8 (pressure gradient) microphone; for sound waves coming from the back, the negative signal from the figure-8 cancels the positive signal from the omnidirectional element, whereas, for sound waves coming from the front, the two add to each other. However, in low frequencies a cardioid microphone behaves as an omnidirectional microphone.


title: Microphone

text: By combining the two components in different ratios, any pattern between omni and figure-8 can be achieved, which comprise the first-order cardioid family. Common shapes include:


title: Microphone

text: Three such cardioid microphones/hydrophones could be orthogonally oriented as a collocated triad to improve the gain and also create a steerable beampattern.


title: Microphone

text: "Figure 8" or bi-directional microphones receive sound equally from both the front and back of the element. Most ribbon microphones are of this pattern. In principle they do not respond to sound pressure at all, only to the "change" in pressure between front and back; since sound arriving from the side reaches front and back equally there is no difference in pressure and therefore no sensitivity to sound from that direction. In more mathematical terms, while omnidirectional microphones are scalar transducers responding to pressure from any direction, bi-directional microphones are vector transducers responding to the gradient along an axis normal to the plane of the diaphragm. This also has the effect of inverting the output polarity for sounds arriving from the back side.


title: Microphone

text: Shotgun microphones are the most highly directional of simple first-order unidirectional types. At low frequencies, they have the classic polar response of a hypercardioid but at medium and higher frequencies an interference tube gives them an increased forward response. This is achieved by a process of cancellation of off-axis waves entering the longitudinal array of slots. A consequence of this technique is the presence of some rear lobes that vary in level and angle with frequency and can cause some coloration effects. Due to the narrowness of their forward sensitivity, shotgun microphones are commonly used on television and film sets, in stadiums, and for field recording of wildlife.


title: Microphone

text: Several approaches have been developed for effectively using a microphone in less-than-ideal acoustic spaces, which often suffer from excessive reflections from one or more of the surfaces (boundaries) that make up the space. If the microphone is placed in, or very close to, one of these boundaries, the reflections from that surface have the same timing as the direct sound, thus giving the microphone a hemispherical polar pattern and improved intelligibility. Initially, this was done by placing an ordinary microphone adjacent to the surface, sometimes in a block of acoustically transparent foam. Sound engineers Ed Long and Ron Wickersham developed the concept of placing the diaphragm parallel to and facing the boundary. While the patent has expired, "Pressure Zone Microphone" and "PZM" are still active trademarks of Crown International, and the generic term boundary microphone is preferred.


title: Microphone

text: While a boundary microphone was initially implemented using an omnidirectional element, it is also possible to mount a directional microphone close enough to the surface to gain some of the benefits of this technique while retaining the directional properties of the element. Crown's trademark on this approach is "Phase Coherent Cardioid" or "PCC," but there are other makers who employ this technique as well.


title: Microphone

text: A lavalier microphone is made for hands-free operation. These small microphones are worn on the body. Originally, they were held in place with a lanyard worn around the neck, but more often they are fastened to clothing with a clip, pin, tape or magnet. The lavalier cord may be hidden by clothes and either run to an RF transmitter in a pocket or clipped to a belt (for mobile use), or run directly to the mixer (for stationary applications).


title: Microphone

text: A wireless microphone transmits the audio as a radio or optical signal rather than via a cable. It usually sends its signal using a small FM radio transmitter to a nearby receiver connected to the sound system, but it can also use infrared waves if the transmitter and receiver are within sight of each other.


title: Microphone

text: A contact microphone picks up vibrations directly from a solid surface or object, as opposed to sound vibrations carried through air. One use for this is to detect sounds of a very low level, such as those from small objects or insects. The microphone commonly consists of a magnetic (moving coil) transducer, contact plate and contact pin. The contact plate is placed directly on the vibrating part of a musical instrument or other surface, and the contact pin transfers vibrations to the coil. Contact microphones have been used to pick up the sound of a snail's heartbeat and the footsteps of ants. A portable version of this microphone has recently been developed. A throat microphone is a variant of the contact microphone that picks up speech directly from a person's throat, which it is strapped to. This lets the device be used in areas with ambient sounds that would otherwise make the speaker inaudible.


title: Microphone

text: A parabolic microphone uses a parabolic reflector to collect and focus sound waves onto a microphone receiver, in much the same way that a parabolic antenna (e.g. satellite dish) does with radio waves. Typical uses of this microphone, which has unusually focused front sensitivity and can pick up sounds from many meters away, include nature recording, outdoor sporting events, eavesdropping, law enforcement, and even espionage. Parabolic microphones are not typically used for standard recording applications, because they tend to have a poor low-frequency response as a side effect of their design.


title: Microphone

text: A stereo microphone integrates two microphones in one unit to produce a stereophonic signal. A stereo microphone is often used for broadcast applications or field recording where it would be impractical to configure two separate condenser microphones in a classic X-Y configuration (see microphone practice) for stereophonic recording. Some such microphones have an adjustable angle of coverage between the two channels.


title: Microphone

text: A noise-canceling microphone is a highly directional design intended for noisy environments. One such use is in aircraft cockpits where they are normally installed as boom microphones on headsets. Another use is in live event support on loud concert stages for vocalists involved with live performances. Many noise-canceling microphones combine signals received from two diaphragms that are in opposite electrical polarity or are processed electronically. In dual diaphragm designs, the main diaphragm is mounted closest to the intended source and the second is positioned farther away from the source so that it can pick up environmental sounds to be subtracted from the main diaphragm's signal. After the two signals have been combined, sounds other than the intended source are greatly reduced, substantially increasing intelligibility. Other noise-canceling designs use one diaphragm that is affected by ports open to the sides and rear of the microphone, with the sum being a 16 dB rejection of sounds that are farther away. One noise-canceling headset design using a single diaphragm has been used prominently by vocal artists such as Garth Brooks and Janet Jackson. A few noise-canceling microphones are throat microphones.


title: Microphone

text: Various standard techniques are used with microphones used in sound reinforcement at live performances, or for recording in a studio or on a motion picture set. By suitable arrangement of one or more microphones, desirable features of the sound to be collected can be kept, while rejecting unwanted sounds.


title: Microphone

text: Microphones containing active circuitry, such as most condenser microphones, require power to operate the active components. The first of these used vacuum-tube circuits with a separate power supply unit, using a multi-pin cable and connector. With the advent of solid-state amplification, the power requirements were greatly reduced and it became practical to use the same cable conductors and connector for audio and power. During the 1960s several powering methods were developed, mainly in Europe. The two dominant methods were initially defined in German DIN 45595 as or T-power and DIN 45596 for phantom power. Since the 1980s, phantom power has become much more common, because the same input may be used for both powered and unpowered microphones. In consumer electronics such as DSLRs and camcorders, "plug-in power" is more common, for microphones using a 3.5 mm phone plug connector. Phantom, T-power and plug-in power are described in international standard IEC 61938.


title: Microphone

text: Some microphones use other connectors, such as a 5-pin XLR, or mini XLR for connection to portable equipment. Some lavalier (or "lapel", from the days of attaching the microphone to the news reporter's suit lapel) microphones use a proprietary connector for connection to a wireless transmitter, such as a radio pack. Since 2005, professional-quality microphones with USB connections have begun to appear, designed for direct recording into computer-based software.


title: Microphone

text: When choosing a pre-amplifier for a certain microphone, the microphone’s impedance must be known. Impedance is a frequency dependant electrical characteristic, measured in ohms (Ω), that relates voltage to current. When not concerned with power transfer, signals are generally transferred as varying voltages and this is also the case for microphones. To obtain the highest signal amplitude one uses a method called impedance bridging. In this configuration the output impedance of the microphone should be negligible in comparison with the input impedance of the pre-amplifier (in practice a pre-amp impedance at least 10 times greater than the microphone impedance is recommended). By doing so, the signal is attenuated minimally and almost no power is used in the process.


title: Microphone

text: The main alternative to impedance bridging is impedance matching which maximizes power transfer for a given source impedance. However, this has not been relevant since the early 20th century when amplifiers were very expensive and produced a lot of heat. To reduce the number of amplifiers in telephone lines, power loss needed to be minimal so source and load impedances were matched. A downside to impedance matching is the 6 dB loss in signal that occurs as only half the voltage level appears at the pre-amplifier’s input. Certain ribbon and dynamic microphones however are exceptions, due to the designers' assumption of a certain load impedance being part of the internal electro-acoustical damping circuit of the microphone.


title: Microphone

text: Different microphones can have vastly different impedances and this depends on the design. In passive microphones, this value relates closely to the impedance of the coil (or similar mechanism). In active microphones, this value describes the output impedance of its internal amplifier circuitry.


title: Microphone

text: Low impedance is considered under 600 Ω. Medium impedance is considered between 600 Ω and 10 kΩ. High impedance is above 10 kΩ. Owing to their built-in amplifier, condenser microphones typically have an output impedance between 50 and 200 Ω.


title: Microphone

text: If a microphone is made in high and low impedance versions, the high impedance version has a higher output voltage for a given sound pressure input, and is suitable for use with vacuum-tube guitar amplifiers, for instance, which have a high input impedance and require a relatively high signal input voltage to overcome the tubes' inherent noise. Most professional microphones are low impedance, about 200 Ω or lower. Professional vacuum-tube sound equipment incorporates a transformer that steps up the impedance of the microphone circuit to the high impedance and voltage needed to drive the input tube. External step-up transformers are also available that can be used in-line between a low impedance microphone and a high impedance input.


title: Microphone

text: Low-impedance microphones are generally preferred over high impedance for the following reason: using a high-impedance microphone with a long cable results in high-frequency signal loss due to cable capacitance, which forms a low-pass filter with the microphone output impedance.


title: Microphone

text: The AES42 standard, published by the Audio Engineering Society, defines a digital interface for microphones. Microphones conforming to this standard directly output a digital audio stream through an XLR or XLD male connector, rather than producing an analog output. Digital microphones may be used either with new equipment with appropriate input connections that conform to the AES42 standard, or else via a suitable interface box. Studio-quality microphones that operate in accordance with the AES42 standard are now available from a number of microphone manufacturers.


title: Microphone

text: Because of differences in their construction, microphones have their own characteristic responses to sound. This difference in response produces non-uniform phase and frequency responses. In addition, microphones are not uniformly sensitive to sound pressure and can accept differing levels without distorting. Although for scientific applications microphones with a more uniform response are desirable, this is often not the case for music recording, as the non-uniform response of a microphone can produce a desirable coloration of the sound. There is an international standard for microphone specifications, but few manufacturers adhere to it. As a result, comparison of published data from different manufacturers is difficult because different measurement techniques are used. The Microphone Data Website has collated the technical specifications complete with pictures, response curves and technical data from the microphone manufacturers for every currently listed microphone, and even a few obsolete models, and shows the data for them all in one common format for ease of comparison.. Caution should be used in drawing any solid conclusions from this or any other published data, however, unless it is known that the manufacturer has supplied specifications in accordance with IEC 60268-4.


title: Microphone

text: A frequency response diagram plots the microphone sensitivity in decibels over a range of frequencies (typically 20 Hz to 20 kHz), generally for perfectly on-axis sound (sound arriving at 0° to the capsule). Frequency response may be less informatively stated textually like so: "30 Hz–16 kHz ±3 dB". This is interpreted as meaning a nearly flat, linear, plot between the stated frequencies, with variations in amplitude of no more than plus or minus 3 dB. However, one cannot determine from this information how "smooth" the variations are, nor in what parts of the spectrum they occur. Note that commonly made statements such as "20 Hz–20 kHz" are meaningless without a decibel measure of tolerance. Directional microphones' frequency response varies greatly with distance from the sound source, and with the geometry of the sound source. IEC 60268-4 specifies that frequency response should be measured in "plane progressive wave" conditions (very far away from the source) but this is seldom practical. "Close talking" microphones may be measured with different sound sources and distances, but there is no standard and therefore no way to compare data from different models unless the measurement technique is described.


title: Microphone

text: The self-noise or equivalent input noise level is the sound level that creates the same output voltage as the microphone does in the absence of sound. This represents the lowest point of the microphone's dynamic range, and is particularly important should you wish to record sounds that are quiet. The measure is often stated in dB(A), which is the equivalent loudness of the noise on a decibel scale frequency-weighted for how the ear hears, for example: "15 dBA SPL" (SPL means sound pressure level relative to 20 micropascals). The lower the number the better. Some microphone manufacturers state the noise level using ITU-R 468 noise weighting, which more accurately represents the way we hear noise, but gives a figure some 11–14 dB higher. A quiet microphone typically measures 20 dBA SPL or 32 dB SPL 468-weighted. Very quiet microphones have existed for years for special applications, such the Brüel & Kjaer 4179, with a noise level around 0 dB SPL. Recently some microphones with low noise specifications have been introduced in the studio/entertainment market, such as models from Neumann and Røde that advertise noise levels between 5–7 dBA. Typically this is achieved by altering the frequency response of the capsule and electronics to result in lower noise within the A-weighting curve while broadband noise may be increased.


title: Microphone

text: The maximum SPL the microphone can accept is measured for particular values of total harmonic distortion (THD), typically 0.5%. This amount of distortion is generally inaudible, so one can safely use the microphone at this SPL without harming the recording. Example: "142 dB SPL peak (at 0.5% THD)". The higher the value, the better, although microphones with a very high maximum SPL also have a higher self-noise.


title: Microphone

text: The clipping level is an important indicator of maximum usable level, as the 1% THD figure usually quoted under max SPL is really a very mild level of distortion, quite inaudible especially on brief high peaks. Clipping is much more audible. For some microphones, the clipping level may be much higher than the max SPL.


title: Microphone

text: The dynamic range of a microphone is the difference in SPL between the noise floor and the maximum SPL. If stated on its own, for example, "120 dB", it conveys significantly less information than having the self-noise and maximum SPL figures individually.


title: Microphone

text: Sensitivity indicates how well the microphone converts acoustic pressure to an output voltage. A high sensitivity microphone creates more voltage and so needs less amplification at the mixer or recording device. This is a practical concern but is not directly an indication of the microphone's quality, and in fact the term sensitivity is something of a misnomer, "transduction gain" being perhaps more meaningful, (or just "output level") because true sensitivity is generally set by the noise floor, and too much "sensitivity" in terms of output level compromises the clipping level. There are two common measures. The (preferred) international standard is made in millivolts per pascal at 1 kHz. A higher value indicates greater sensitivity. The older American method is referred to a 1 V/Pa standard and measured in plain decibels, resulting in a negative value. Again, a higher value indicates greater sensitivity, so −60  dB is more sensitive than −70 dB.


title: Microphone

text: Some microphones are intended for testing speakers, measuring noise levels and otherwise quantifying an acoustic experience. These are calibrated transducers and are usually supplied with a calibration certificate that states absolute sensitivity against frequency. The quality of measurement microphones is often referred to using the designations "Class 1," "Type 2," etc., which are references not to microphone specifications but to sound level meters. A more comprehensive standard for the description of measurement microphone performance was recently adopted.


title: Microphone

text: Measurement microphones are generally scalar sensors of pressure; they exhibit an omnidirectional response, limited only by the scattering profile of their physical dimensions. Sound intensity or sound power measurements require pressure-gradient measurements, which are typically made using arrays of at least two microphones, or with hot-wire anemometers.


title: Microphone

text: To take a scientific measurement with a microphone, its precise sensitivity must be known (in volts per pascal). Since this may change over the lifetime of the device, it is necessary to regularly calibrate measurement microphones. This service is offered by some microphone manufacturers and by independent certified testing labs. All microphone calibration is ultimately traceable to primary standards at a national measurement institute such as NPL in the UK, PTB in Germany and NIST in the United States, which most commonly calibrate using the reciprocity primary standard. Measurement microphones calibrated using this method can then be used to calibrate other microphones using comparison calibration techniques.


title: Microphone

text: Depending on the application, measurement microphones must be tested periodically (every year or several months, typically) and after any potentially damaging event, such as being dropped (most such microphones come in foam-padded cases to reduce this risk) or exposed to sounds beyond the acceptable level.


title: Microphone

text: Typically, an array is made up of omnidirectional microphones distributed about the perimeter of a space, linked to a computer that records and interprets the results into a coherent form.


title: Microphone

text: Windscreens (or windshields – the terms are interchangeable) provide a method of reducing the effect of wind on microphones. While pop-screens give protection from unidirectional blasts, foam "hats" shield wind into the grille from all directions, and blimps / zeppelins / baskets entirely enclose the microphone and protect its body as well. The latter is important because, given the extreme low-frequency content of wind noise, vibration induced in the housing of the microphone can contribute substantially to the noise output.


title: Microphone

text: The shielding material used – wire gauze, fabric or foam – is designed to have a significant acoustic impedance. The relatively low particle-velocity air pressure changes that constitute sound waves can pass through with minimal attenuation, but higher particle-velocity wind is impeded to a far greater extent. Increasing the thickness of the material improves wind attenuation but also begins to compromise high-frequency audio content. This limits the practical size of simple foam screens. While foams and wire meshes can be partly or wholly self-supporting, soft fabrics and gauzes require stretching on frames or laminating with coarser structural elements.


title: Microphone

text: Since all wind noise is generated at the first surface the air hits, the greater the spacing between the shield periphery and microphone capsule, the greater the noise attenuation. For an approximately spherical shield, attenuation increases by (approximately) the cube of that distance. Thus larger shields are always much more efficient than smaller ones. With full basket windshields there is an additional pressure chamber effect, first explained by Joerg Wuttke, which, for two-port (pressure gradient) microphones, allows the shield/microphone combination to act as a high-pass acoustic filter.


title: Microphone

text: Since turbulence at a surface is the source of wind noise, reducing gross turbulence can add to noise reduction. Both aerodynamically smooth surfaces, and ones that prevent powerful vortices being generated, have been used successfully. Historically, artificial fur has proved very useful for this purpose since the fibers produce micro-turbulence and absorb energy silently. If not matted by wind and rain, the fur fibers are very transparent acoustically, but the woven or knitted backing can give significant attenuation. As a material, it suffers from being difficult to manufacture with consistency and is hard to keep in pristine condition on location. Thus there is an interest in moving away from its use.


title: Microphone

text: In the studio and on stage, pop-screens and foam shields can be useful for reasons of hygiene and protecting microphones from spittle and sweat. When colored they are useful for identification. On location, the basket shield can contain a suspension system to isolate the microphone from shock and handling noise.


title: Microphone

text: Stating the efficiency of wind noise reduction is an inexact science since the effect varies enormously with frequency, and hence with the bandwidth of the microphone and audio channel. At very low frequencies (10–100 Hz) where massive wind energy exists, reductions are important to avoid overloading of the audio chain – particularly the early stages. This can produce the typical “wumping” sound associated with wind, which is often syllabic muting of the audio due to LF peak limiting. At higher frequencies – 200 Hz to ~3 kHz – the aural sensitivity curve allows us to hear the effect of wind as an addition to the normal noise floor, even though it has a far lower energy content. Simple shields may allow the wind noise to be 10 dB less apparent; better ones can achieve nearer to a 50 dB reduction. However, the acoustic transparency, particularly at HF, should also be indicated, since a very high level of wind attenuation could be associated with very muffled audio.


title: Norwegian Forest cat

text: The Norwegian Forest cat ( and ) is a breed of domestic cat originating in Northern Europe. This natural breed is adapted to a very cold climate, with a top coat of long, glossy, water-shedding hair and a woolly undercoat for insulation. The breed's ancestors may have been a landrace of short-haired cats brought to Norway about A.D. 1000 by the Vikings, who may also have brought with them long-haired cats, like those ancestral to the modern Siberian and Turkish Angora. During World War II, the Norwegian Forest cat was nearly extinct; then the Norwegian Forest Cat Club's breeding program increased the cat's number. It was registered as a breed with the European Fédération Internationale Féline in the 1970s, when a cat fancier, Carl-Fredrik Nordane, took notice of the breed and made efforts to register it. The breed is very popular in Norway, Denmark, Sweden, Iceland, and France.


title: Norwegian Forest cat

text: It is a big, strong cat, similar to the Maine Coon breed, with long legs, a bushy tail, and a sturdy body. It is very good at climbing, partly because of strong claws. The lifespan is usually 14 to 16 years. Kidney and heart diseases have been reported in the breed. Specifically in this breed, complex rearrangements of glycogen branching enzyme (GBE1) can cause a perinatal hypoglycaemic collapse and a late-juvenile-onset neuromuscular degeneration in glycogen storage disease type IV.


title: Norwegian Forest cat

text: The Norwegian Forest cat is adapted to survive Norway's cold weather. Its ancestors may include cold-adapted black and white British shorthair cats brought to Norway from Great Britain some time after 1000 AD by the Vikings, and longhaired cats brought to Norway by Crusaders around the 14th century. These cats could have reproduced with farm and feral stock and may have eventually evolved into the modern-day Norwegian Forest breed. The Siberian and the Turkish Angora, longhaired cats from Russia and Turkey, respectively, are also possible ancestors of the breed. Norse legends refer to the as a "mountain-dwelling fairy cat with an ability to climb sheer rock faces that other cats could not manage." Since the Norwegian Forest cat is a very adept climber, author Claire Bessant believes that the folktale could be about the ancestor of the modern Norwegian Forest breed. The name "Norse" is used by some breeders and fancier organisations for the modern breed.


title: Norwegian Forest cat

text: Most likely the ancestors of the Norwegian Forest cat served as ships' cats (mousers) on Viking ships. The original landrace lived in the Norwegian forests for many centuries, but were later prized for their hunting skills and were used on Norwegian farms, until they were discovered in the early 20th century by cat enthusiasts.


title: Norwegian Forest cat

text: In 1938 the first organisation devoted to the breed, the Norwegian Forest Cat Club, was formed in Oslo, Norway. The club's movement to preserve the breed was interrupted by World War II. Owing to cross-breeding with free-ranging domestic cats during the war, the Norwegian Forest cat became endangered and nearly extinct until the Norwegian Forest Cat Club helped the breed make a comeback by developing an official breeding program. In the 1950s, King Olav V declared them the official cat of Norway. Since the cat did not leave Norway until the 1970s, it was not registered as a breed in the Fédération Internationale Féline (FIFe), the pan-European federation of cat registries, until Carl-Fredrik Nordane, a Norwegian cat fancier, took notice of the breed, and made efforts to register it. The breed was registered in Europe by the 1970s, and in the American Cat Fanciers Association in 1994. In 1978, it was recognized in Sweden as an official breed, and in 1989, they were accepted as a breed in the United Kingdom by the Norwegian Cat Club of Britain.


title: Norwegian Forest cat

text: The Norwegian Forest breed is very popular in Norway and Sweden. Since 2003, it has been the fifth most popular cat breed in France, where there are about 400 to 500 births per year.


title: Norwegian Forest cat

text: The Norwegian Forest cat is strongly built and larger than an average cat. Adult females weigh ; males, . The breed has a long, sturdy body; long legs; and a bushy tail. The coat consists of a long, thick, glossy, water-repellent top layer and a woolly undercoat and is thickest at the legs, chest, and head. The undercoat appears as a ruff. The profile of the breed is generally straight. Their water-resistant coat with a dense undercoat developed to help the cat survive in the harsh Scandinavian climate.


title: Norwegian Forest cat

text: The head is long with an overall shape similar to an equilateral triangle, a strong chin, and a muzzle of medium length; a square or round-shaped head is considered to be a defect. The eyes are almond shaped and oblique, and may be of any colour. The ears are large, wide at the base, and high set, have a tufted top, are placed in the extension of the triangle formed by the head, and end with a tuft of hair like the ears of the lynx. All coat colors and divisions in the traditional, sepia and mink categories are accepted. Since the cats have very strong claws, they are very good climbers, and can even climb rocks.


title: Norwegian Forest cat

text: Norwegian Forest cats that live primarily outdoors become swift and effective hunters, but the breed can also adapt to indoor life. The cats usually live to be 14 to 16 years old. As they are heavy-boned and tall, they eat more food than most other domestic breeds.


title: Norwegian Forest cat

text: They are friendly, intelligent, and generally good with people. The Norwegian Forest cat has a lot of energy. They are very interactive cats who enjoy being part of their family environment and love to play games. Fanciers note that these cats produce a variety of high-pitched "chirping" vocalizations.


title: Norwegian Forest cat

text: Kidney and heart diseases have been reported in the breed. In an experiment directed by John C. Fyfea, Rebeccah L. Kurzhals, and others, it was concluded that a complex rearrangement in the breed's Glycogen branching enzyme (GBE1) can cause both a perinatal hypoglycemic collapse and a late-juvenile-onset neuromuscular degeneration in glycogen storage disease type IV in the breed. This disorder, while rare, can prove fatal to cats that have it. There are DNA tests available for GSD IV, and it is highly recommended (some cat associations obligate their Norwegian Forest cat breeder members) to carry out the DNA test before using such animals for breeding. PawPeds provide a pedigree database which comes together with health programmes, through publishing each single cat's test result, to provide useful information for breeders to make a well-informed breeding decision. The breed has also been known to suffer from hip dysplasia, which is a rare, partially hereditary disease of the hip joint.


title: Norwegian Forest cat

text: Patella luxation is found more in the British Shorthair, Abyssinian and Devon Rex breeds, but it is recognized in Norwegian Forest cats as well. It is a condition in which patella moves out of its original physiological position.


title: Norwegian Forest cat

text: A pedigree with 871 Norwegian Forest cats shows familial cardiomyopathy in this breed. There is also high prevalence of eosinophilic granuloma complex in Norwegian Forest cats which is suggestive of a genetic background.


title: Norwegian Forest cat

text: The main factors causing "Toxoplasma gondii" seropositivity on cats are age, raw meat and outdoor access. A study shows that "T. gondii" seropositivity varies by cat breeds. Norwegian Forest cats have a relatively high rate of "Toxoplasma gondii" seropositivity (4.66%) comparing with other pure-bred cats (Birman: 4.16%, British Shorthair: 3.39%, Korat: 2.03%, Ocicat: 4.26%, Siamese: 2.57%), but slightly lower than Persian cats (6.99%).


title: Norwegian Forest cat

text: Glycogen storage disease type IV due to branching enzyme deficiency was found in an inbred family of Norwegian forest cats.


title: Antihistamine

text: Antihistamines are drugs which treat allergic rhinitis, common cold, influenza, and other allergies. Typically, people take antihistamines as an inexpensive, generic (not patented) drug that can be bought without a prescription and provides relief from nasal congestion, sneezing, or hives caused by pollen, dust mites, or animal allergy with few side effects. Antihistamines are usually for short-term treatment. Chronic allergies increase the risk of health problems which antihistamines might not treat, including asthma, sinusitis, and lower respiratory tract infection. Consultation of a medical professional is recommended for those who intend to take antihistamines for longer-term use.


title: Antihistamine

text: Although people typically use the word "antihistamine" to describe drugs for treating allergies, doctors and scientists use the term to describe a class of drug that opposes the activity of histamine receptors in the body. In this sense of the word, antihistamines are subclassified according to the histamine receptor that they act upon. The two largest classes of antihistamines are H-antihistamines and H-antihistamines.


title: Antihistamine

text: H-antihistamines work by binding to histamine H receptors in mast cells, smooth muscle, and endothelium in the body as well as in the tuberomammillary nucleus in the brain. Antihistamines that target the histamine H-receptor are used to treat allergic reactions in the nose (e.g., itching, runny nose, and sneezing). In addition, they may be used to treat insomnia, motion sickness, or vertigo caused by problems with the inner ear. H-antihistamines bind to histamine H receptors in the upper gastrointestinal tract, primarily in the stomach. Antihistamines that target the histamine H-receptor are used to treat gastric acid conditions (e.g., peptic ulcers and acid reflux). Other antihistamines also target H receptors and H receptors.


title: Antihistamine

text: Histamine receptors exhibit constitutive activity, so antihistamines can function as either a neutral receptor antagonist or an inverse agonist at histamine receptors. Only a few currently marketed H-antihistamines are known to function as inverse agonists.


title: Antihistamine

text: Histamine makes blood vessels more permeable (vascular permeability), causing fluid to escape from capillaries into tissues, which leads to the classic symptoms of an allergic reaction — a runny nose and watery eyes. Histamine also promotes angiogenesis.


title: Antihistamine

text: Antihistamines suppress the histamine-induced wheal response (swelling) and flare response (vasodilation) by blocking the binding of histamine to its receptors or reducing histamine receptor activity on nerves, vascular smooth muscle, glandular cells, endothelium, and mast cells. Antihistamines can also help correct Eustachian Tube dysfunction, thereby helping correct problems such as muffled hearing, fullness in the ear and even tinnitus.


title: Antihistamine

text: Itching, sneezing, and inflammatory responses are suppressed by antihistamines that act on H1-receptors. In 2014, antihistamines such as desloratadine were found to be effective to complement standardized treatment of acne due to their anti-inflammatory properties and their ability to suppress sebum production.


title: Antihistamine

text: H-antihistamines refer to compounds that inhibit the activity of the H receptor. Since the H receptor exhibits constitutive activity, H-antihistamines can be either neutral receptor antagonists or inverse agonists. Normally, histamine binds to the H receptor and heightens the receptor's activity; the receptor antagonists work by binding to the receptor and blocking the activation of the receptor by histamine; by comparison, the inverse agonists bind to the receptor and both block the binding of histamine, and reduce its constitutive activity, an effect which is opposite to histamine's. Most antihistamines are inverse agonists at the H receptor, but it was previously thought that they were antagonists.


title: Antihistamine

text: Clinically, H-antihistamines are used to treat allergic reactions and mast cell-related disorders. Sedation is a common side effect of H-antihistamines that readily cross the blood–brain barrier; some of these drugs, such as diphenhydramine and doxylamine, may therefore be used to treat insomnia. H-antihistamines can also reduce inflammation, since the expression of NF-κB, the transcription factor the regulates inflammatory processes, is promoted by both the receptor's constitutive activity and agonist (i.e., histamine) binding at the H receptor.


title: Antihistamine

text: A combination of these effects, and in some cases metabolic ones as well, lead to most first-generation antihistamines having analgesic-sparing (potentiating) effects on opioid analgesics and to some extent with non-opioid ones as well. The most common antihistamines utilized for this purpose include hydroxyzine, promethazine (enzyme induction especially helps with codeine and similar prodrug opioids), phenyltoloxamine, orphenadrine, and tripelennamine; some may also have intrinsic analgesic properties of their own, orphenadrine being an example.


title: Antihistamine

text: Second-generation antihistamines cross the blood–brain barrier to a much lesser extent than the first-generation antihistamines. They minimize sedatory effects due to their focused effect on peripheral histamine receptors. However, upon high doses second-generation antihistamines will begin to act on the central nervous system and thus can induce drowsiness when ingested in higher quantity. Additionally, some second-generation antihistamines, notably cetirizine, can interact with CNS psychoactive drugs such as bupropion and benzodiazepines.


title: Antihistamine

text: H-antihistamines, like H-antihistamines, exist as inverse agonists and neutral antagonists. They act on H histamine receptors found mainly in the parietal cells of the gastric mucosa, which are part of the endogenous signaling pathway for gastric acid secretion. Normally, histamine acts on H to stimulate acid secretion; drugs that inhibit H signaling thus reduce the secretion of gastric acid.


title: Antihistamine

text: H-antihistamines are among first-line therapy to treat gastrointestinal conditions including peptic ulcers and gastroesophageal reflux disease. Some formulations are available over the counter. Most side effects are due to cross-reactivity with unintended receptors. Cimetidine, for example, is notorious for antagonizing androgenic testosterone and DHT receptors at high doses.


title: Antihistamine

text: An H-antihistamine is a classification of drugs used to inhibit the action of histamine at the H receptor. H receptors are primarily found in the brain and are inhibitory autoreceptors located on histaminergic nerve terminals, which modulate the release of histamine. Histamine release in the brain triggers secondary release of excitatory neurotransmitters such as glutamate and acetylcholine via stimulation of H receptors in the cerebral cortex. Consequently, unlike the H-antihistamines which are sedating, H-antihistamines have stimulant and cognition-modulating effects.


title: Antihistamine

text: The first H receptor antagonists were discovered in the 1930s and these drugs were marketed in the 1940s. Piperoxan was discovered in 1933 and was the first compound with antihistamine effects to be identified. However, piperoxan and its analogues were too toxic to be used in humans. Phenbenzamine (Antergan) was the first clinically useful antihistamine and was introduced for medical use in 1942. Subsequently, many other antihistamines were developed and marketed. Diphenhydramine (Benadryl) was synthesized in 1943, tripelennamine (Pyribenzamine) was patented in 1946, and promethazine (Phenergan) was synthesized in 1947 and launched in 1949. By 1950, at least 20 different antihistamines had been marketed. Chlorphenamine (Piriton), a less sedating antihistamine, was synthesized in 1951, and hydroxyzine (Atarax, Vistaril), an antihistamine used specifically as a sedative and tranquilizer, was developed in 1956. The first non-sedating antihistamine was terfenadine (Seldane) and was developed in 1973. Subsequently, other non-sedating antihistamines like loratadine (Claritin), cetirizine (Zyrtec), and fexofenadine (Allegra) were developed and introduced.


title: Antihistamine

text: The introduction of the first-generation antihistamines marked the beginning of medical treatment of nasal allergies. Research into these drugs led to the discovery that they were H receptor antagonists and also to the development of H receptor antagonists, where H-antihistamines affected the nose and the H-antihistamines affected the stomach. This history has led to contemporary research into drugs which are H receptor antagonists and which affect the H receptor antagonists. Currently most people who use an H receptor antagonist to treat allergies use a second- or third-generation drug.


title: Antihistamine

text: The United States government removed two second generation antihistamines, terfenadine and astemizole, from the market based on evidence that they could cause heart problems.