SPL and hearing loss

Charles Rose

I have read many a thread referring to SPLs in excess of 110 db.
A question I have is why would any desire to listen to music at that level?

This may be worth a read:

Decibel
Level

30 Quiet library, soft whispers
40 Living room, refrigerator, bedroom away from traffic
50 Light traffic, normal conversation, quiet office
60 Air conditioner at 20 feet away, sewing machine
70 Vacuum cleaner, hair dryer, noisy restaurant
80 Average city traffic, garbade disposals, alarm clock
at two feet.

The following noises can be dangerous under constant
exposure:

90 Subway, motorcycle, truck traffic, lawn mower
100 Garbage truck, chain saw, pneumatic drill (very loud stereo
music)
120 Rock band concert in front of speakers, thunderclap
140 Gunshot blast, jet plane
180 Rocket launching pad


The louder it gets increases the likelyhood of permanent hearing loss. Listening to music at levels above 90dB will greatly increase the chance permanent hearing loss.

CR


:rolleyes:

wlrandall

There's a difference between merely hearing music and totally experiencing it by hearing and feeling it. I prefer the latter...but only for short periods.

Dr. Spec

There was a big thread about this over at HTF.

The human ear is most sensitive to midrange frequencies, and that is why OSHA requires the use of the A-Weighted scale for noise monitoring at work.

The A-Weighted scale filters noise below 500 Hz and cuts out much of the low frequencies. If you look at the time-weighted average (TWA) ratings for SPL vs. duration you will see the A-Weighted scale is always referenced.

So 110 dB at 25 Hz actual sound pressure level will be some ridicuolusly low reading on the A-weighted scale of the SPL meter. In other words, OSHA isn't worried about low frequencies nearly as much as the midrange stuff.

If I listen to music, the average SPL in the midrange frequencies is probably about 85 dB. Same for HT. But the bass frequencies are always cooked hot for HT DVDs and the LFE channel is boosted 10 dB in relation to the other channels anyway, so you end up with SPL peaks in the 105-110 dB (or higher) range for deep bass frequencies, but they never last very long (a few seconds at the most) and then the average SPL returns to the safe and tolerable 80-90 dB region for the more damaging midrange stuff.

FWIW, I always wear hearing protection while at work on the production floor, while hunting with a firearm larger than a .22 LR, and while operating power tools, lawn movers, weed whackers, etc.

Strong Bad

Huh? What? Did someone say something?

VR3

Duration
(Hours) Sound Level
Slow Response

32.0 80
27.9 81
24.3 82
21.1 83
18.4 84
16.0 as
13.9 86
12.1 87
10.6 88
9.2 89
8.0 90
7.0 91
6.2 92
5.3 93
4.6 94
4.0 95
3.5 96
3.0 97
2.6 98
2.3 99
2.0 100
1.7 101
1.5 102
1.4 103
1.3 104
1.0 105

madmax

Originally posted by Dr. Spec
There was a big thread about this over at HTF.

The human ear is most sensitive to midrange frequencies, and that is why OSHA requires the use of the A-Weighted scale for noise monitoring at work.

The A-Weighted scale filters noise below 500 Hz and cuts out much of the low frequencies. If you look at the time-weighted average (TWA) ratings for SPL vs. duration you will see the A-Weighted scale is always referenced.

So 110 dB at 25 Hz actual sound pressure level will be some ridicuolusly low reading on the A-weighted scale of the SPL meter. In other words, OSHA isn't worried about low frequencies nearly as much as the midrange stuff.

I'm not disputing any of this but I wouldn't write off the dangers of bass energy based on OSHA. I'll bet the ratio of jobs with high level midrange noise is far greater than jobs with high level bass energy. Maybe OSHA considers midrange noise much more of a problem because of the sheer percentages. I'm sure they exist but I can't really think of any job related noise in the 20 to 80 hz with an intensity of over 110db.
madmax

Dr. Spec

Quite possible, madmax. I'll see what I can dig up on this.