Accoustic Illusions – How We Perceive the Sounds that Surround Us

This is a very interesting video about different aspects of music. It begins with an introduction about the relation between maths and music, talking about the greek philosopher Pitagoras who wrote about the relation between the length of a string and the musical note it produces and then divides the string into different portions, obtaining different musical notes. After these facts about the mathematical relation between the notes, the video continues to the ‘timbre’ which is the part of the sound that makes it identifiable as the sound of a certain instrument. The timbre depends on the mixture of harmonics that vibrate together with the original note. Only synthesizers can play notes without harmonics, all other instruments produce a musical note with a timbre composed by several harmonics of this note.
Then it becomes really interesting: It looks like musical perception does not depend on the musical facts alone but has to do with the culture where the individual grew up. Diana Deutsch shows how a simple interval is perceived as ascending or as descending, depending on the culture of the listener! Culture relates here to the mother tongue or language of the individual.
The video mentions that right handed people from all cultures tend to perceive the low tones on the left side and the higher pitches on the right side while left handed and ambidextrous people perceive music the other way around. This is the reason for the disposition of the elements in an symphonic orchestra. If the elements weren’t ordered the way they are, the musicians couldn’t hear well the other instruments in the orchestra. However, since the orchestras are normally in front of the public, it results that the public must listen the music in an ‘unnatural’ perspective.
The video then mentions a test that shows how our perception is distorted: the listener receives some musica sounds through the headphones and has to decide wethere the low pitches sound on the right or on the left side. Once the person is sure about what he/she is hearing, the person shall swap the sides of the earphones so that the left chanel now is the right chanel and vice versa. One expects that now the low pitches should come from the opposite side. However, this is not the case! People continue to hear the low notes at the same location, no matter where they are really located, spatially speaking.
The video continues to other interesting aspects of music and we recommend to watch it right away, if you are interested in the part about accoustic illusions, you might want to go directly to minute 16.