Ottawa, the band Kiss recorded an SPL of 136 dB measured during their live performance. Noise complaints from residents in the area eventually forced the band to turn the volume down. (136 dB is approximately the threshold of pain, and about as loud as a jet taking off away, or the loudest human voice shouting away from the ear.) Deafening sound Loud sounds have long been known to cause damage to ears. In Norway, this fact was proved for coppersmiths as far back as 1731. Acoustic instruments may represent a risk for hearing damage, especially with lengthy exercising in rooms with high reverberation. 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 dB(A) at average may be risky even after 30 seconds, 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. The Control of Noise at Work Regulations 2005 introduced safety limits for daily noise exposure in the UK like 92 dB(A) as average during 30 minutes. Parodies The notion of "loudness equals greatness" pervades rock music to the extent that it has been satirized. In the mockumentary This Is Spinal Tap, the band is presented by the fictional filmmaker Marty di Bergi as "one of England's loudest bands". One popular joke from the film features Nigel Tufnel displaying the band's amplifiers which are calibrated up to 11, instead of up to 10, allowing them to go "one louder". As a consequence of this, manufacturers began making amplifiers with knobs that went up to 11, or even higher, with Eddie Van Halen reputedly being the first to purchase one. Marshall, the company that provided amplifiers for the film that the custom marked knobs were applied to, now sells amplifiers such as its JCM900 (first sold in 1990) whose knobs are marked from 0 to 20. The fictional band Disaster Area (appearing in Douglas Adams's The Restaurant at the End of the Universe) plays concerts which can literally devastate entire planets. The audience listens from a specially-constructed concrete bunker some thirty miles from the stage, and the band plays