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Posted by Lloyd Burns, Coach on team #188, Woburn Robotics, from Woburn Collegiate and Canada 3000, ScotiaBank, Royal Bank Financial.

Posted on 4/28/99 5:08 PM MST



Just so you know, I used a Radio Shack Sound Level Meter to sample levels in three areas.

Einstein - 100 dB C weighting (flat), 86 dB A weighting - at the edge of the seating area in the front rows of seats, and in front of the operators 'tent' at the front of the bleachers, going down to 90 dB C at the top of the upper stairs of the bleachers (central bleachers)
Newton - 90 dB C, about 80 dB A, near the speakers, as above.
Pits - Announcer 95 dB C, Einstein feed (when pit announcer was not talking) 100 dB - measured at the 188 pit area.

I have no reason to believe that it is grossly 'out of kilter' :-), but have never calibrated the instrument.

OSHA requires employer action at levels above 85 dB, but because the relation between the A and C scales was ignored by the legislation, the level is 85 dB A, not C, even though the C weighting corresponds more closely to the levels at which there is danger. The feeling I get from occasional readings, and talks by acoustics profs at various U's, suggest that the high-volume bass is just as efficient at destroying hearing as the high-volume treble legislated against with A scale readings. (A and C scales are nearly the same, from 1 to 20 kHz, but C is flat, while A droops 20 dB down from 1000 Hz at 100 Hz (HP Acoustics Handbook (Nov '68), Application Note 100, p75)). There is a lot of energy in the Bass, judging by the A vs C reading I got.

P.S. I'm the guy running around with the Hard Hat with the Hellberg ear defenders (I got three staples in my scalp last year in a pit accident, and I found the sound levels Oppressive, Last year; this year, no wounds, and the quiet (27 dB attenuation) was pleasant, and I could still converse with only a little inconvenience!)