Inspired by AO's CPU-meter, I suggest a necktie with 10 LEDs (perhaps 7 green, 1 yellow, 2 red) driven by one of those bargraph display chips (LM18??). The number of LEDs lit indicates the sound level nearby - mostly green is OK, yellow means caution, frequent red LEDs means "lower your voice please!" or some less refined retort.
A small electret microphone will be located in the tie clip, the power source a 9-v battery located in a pocket in the bottom of the tie (an additional benefit - ballast to keep the tie straight!)
Should this become popular, it could mitigate the "rising tide of noise" endured in many restaurants and elsewhere - the ambient noise caused by many simultaneous conversations causes everyone to shout, thereby increasing the problem.
If enough stalwart gentlemen (and ladies - could be implemented in an attractive scarf, as well) were to wear these routinely, public life might take on a more civilized tone.-- csea, Mar 17 2004 T-equalizer http://www.thinkgee...hirts/generic/8a5b/Similar sound sensitive clothing [csea, Jul 15 2007] Perhaps, somehow, the picture could change.-- Detly, Mar 17 2004 Since the body of the wearer would block some sound from his/her back the instrument is (somewhat) directional. Useful for early warning and avoidance of approaching life-insurance salesman, angry persons, freight trains, drunken kareoke wanna-bes, and other loud undesirables. +-- RooneDitoff, Mar 17 2004 Someone seems to have baked a similar concept, though it actually has only 5 levels including "off." [link]-- csea, Jul 15 2007 random, halfbakery