OSHA Noise Standards and FIRST Events

[Al Skierkiewicz]

To bring this around again and introduce some added info...
1. Check out http://www.kellrobotics.org/files/Sound_2008.pdf where there is some data taken during the Championship. Please note the 6-8dB average to peak readings. This is about the amount of compression audio mixers employee to keep the average level sounding loud.
2. Long exposure to high level sound casues temporary threshold shift. (i.e. loud today doesn't sound as loud as yesterday)
3. OHSHA standards look at weighted (filtered) data averaged over time (8hr/day, 5 day week). They recognize 85dBA as loud and 90dBA as harmful repetitive exposure requiring hearing protection.
4. Noise above certain levels causes permanent damage. i.e. A nerve is damaged beyond repair or a sensor will give false data forever (ringing).
5. In the real world, speaker systems do not cover a sound field with uniform sound level. Those in direct line with the front of the speaker array usually will experience the highest sound level. Sound designers on occassion will use "fill" speakers to cover a difficult area like that directly beneath the main array.
6. Speakers on the floor are usually sub woofers which reproduce sound below the frequency response of the A weighting filter and are therefore not included in the data. They move a lot of air and do seem to move clothing when standing nearby but do not contribute significantly to hearing loss at normal levels. They do allow you to "feel" the music though.
7. It is evident from the data, that levels jumped during cheering and matches.
I think it is evident that there is an issue with high levels during some parts of the day and average levels are on the borderline of needing hearing protection. That does require some action to be taken in my opinion. Overall levels could be reduced by a few dB and certainly levels could be reduced during those times that cheering takes place so as to not disrupt the overall feel of the competition but hearing is somewhat protected. For those who will spend a lot of time in the stands please encourage hearing protection of some kind during the day. McMaster Carr has a fine selection of disposable protectors. I keep part number 9159T5 headphone types for comfortable everyday/all day protection and 54725T32 disposable for short periods like camera and floor people during Soundstage tapings.