 However, the sound level and the risk have increased with more powerful amplifiers and loudspeakers, and the volume at some concerts is far above the level which may induce such damage without ear protection.115 dBA (decibel-A) at average may be risky even after 30 seconds, and a 10 dB increase means increasing the sound level by a factor of ten (an angle grinder at 1 m gives about 100 dBA, and in UK, Norway, etc., it is strictly prohibited for workers to use it more than a few minutes without ear protection).The sound level claimed at some of Manowar's performances may cause ear damage almost immediately; the phrase "deafening sound" should be taken literally.