SPL vs HZ vs My Hearing

[Eric_C]

I've asked this question before but never got a clear answer.

Am I safe to assume that a very "boring" 85db is a safe listening level. I don't mind easy listening stuff that low but I do like to turn it up once in a while.

What makes me wonder is how does hz level play into it.

I was listening to the White Stripes tonight, it has a very low hz bass line that registered nearly 100db but it was far from loud. When the bass line stopped and the woman was singing it barely got over 80db.

Is over 85db unacceptable at any level?

I've read all the guide lines and they are pretty broad to interpretation. I have quite a loud setup in my car and I also road race the car with open headers. I've put the SPL meter in the car for a few laps and I get over 95db inside the car just from the exhaust. With my helmet on I probably drop 15 off of that but I've stood at the starting line for top fuel cars before, love to play it loud and my hearing seems sharp as ever.

The only time I scared myself was I listened to Refused: The Shape of Punk to Come on DVD-A. I really cranked it up and at the end of the album it was around 103db. I had to shake my head a few times after that one but things seemed no worse for wear.

Right now I'm listening to Tara Maclean's silence which is just her singing and a string guitar, zero bass. Its pretty loud to my ears but only barely touching over 81db when she is really whaling. Next track is Red with a bass line, 90db but thats just because of the bass which is nearly inaudible.

So whats the verdict? Anyone have a solid answer?

[David Meek]

This may help:

weakest sound heard 0 dB
normal conversation at 3-5 ft 60-70 dB
dial tone of telephone 80 dB
city traffic inside car 85 dB

1983 OSHA monitoring requirements begin at 90 dB

train whistle at 500 ft. 90 dB
subway train at 200 ft. 95 dB

regular sustained exposure may cause permanent damage 90-95 dB

power mower 107 dB
power saw 110 dB

Pain begins 125 dB

pneumatic riveter at 4 ft. 125 dB
jet engine at 100 ft. 140 dB
loudest sound that can occur 194 dB

Musical Noise

normal piano practice 60-70 dB
fortissimo singer 3 ft. away 70 dB
chamber music in small auditorium 75-85 dB
piano fortissimo 92-95 dB
violin 84-103 dB
cello 82-92 dB
oboe 90-94 dB
flute 85-111 dB
piccolo 95-112 dB
clarinet 92-103 dB
french horn 90-106 dB
trombone 85-114 dB
timpani & bass drum rolls 106 dB
average Walkman on 5/10 setting 94 dB
symphonic music peak 120-137 dB
amplified rock music at 4-6 ft. 120 dB
rock music peak 150 dB

[Paul H]

...

I've read all the guide lines and they are pretty broad to interpretation. I have quite a loud setup in my car and I also road race the car with open headers. I've put the SPL meter in the car for a few laps and I get over 95db inside the car just from the exhaust. With my helmet on I probably drop 15 off of that but I've stood at the starting line for top fuel cars before, love to play it loud and my hearing seems sharp as ever.
...

Hearing damage is largely slow, over a long time of months and years, and not noticeable to the person getting damaged - your baseline is changing slowly and there is no way to recognize it yourself.

It's a similar situation to all the people who've gotten eyeglasses and can't believe all the detail they're suddenly seeing - that they never even knew they were missing.

If you're watching racing, around the pits or especially if you're on the track, wear plugs inside your helmet. I do motorcycle track days and wear them most of the day and always when I'm on the track.

[Eric_C]

Maybe I didn't explain clear enough.

Is 110db in the 30hz range as bad as 110hz at 1khz?.

On some music you can register near 100db on the low scale but when your playing in the mid-tweeter range its only in the 80db range.

So is low freq as dangerous at high db as high freq at the same db.

[Chris7]

Low frequencies are not as dangerous. Industrial and health-related SPL guidelines are typically given using an A-weighting, which is 20dB down at 100 Hz and 30dB down at 50 Hz.

The reason typical bass-heavy music has higher SPLs in the bass region is because of the ear's natural equal loudness contour.

[Eric_C]

Oh so when I look at those charts, those are at A weighting?

No kidding!

Well if thats true time to turn it up

[Chris7]

Yes, the charts showing loudness guidelines from various agencies are almost always using an A weighting, e.g.:

http://www.osha.gov/pls/oshaweb/owadisp.show_document?p_id=9735&p_table=STANDARDS

I can't remember where I read that this was physiologically realistic, but I have seen it confirmed somewhere. In any case, if you're going by absolute SPLs, not an A-weighting, the key danger zone is the 2kHz-5kHz region, where exposure-related hearing loss usually begins.

[Kal Rubinson]

Maybe I didn't explain clear enough.

Is 110db in the 30hz range as bad as 110hz at 1khz?.

On some music you can register near 100db on the low scale but when your playing in the mid-tweeter range its only in the 80db range.

So is low freq as dangerous at high db as high freq at the same db.

It is most dangerous in the middle where we have the lowest threshhold. At both high and low frequencies our high threshholds are somewhat protective.

Kal

[Chris D]

This may help:

loudest sound that can occur 194 dB

That's interesting, David, and a good post. I wonder why that particular thing would be stated, though, that there's a limit to volume? I don't see how that could be true, but I'm very intrigued.

[Chris7]

That's interesting, David, and a good post. I wonder why that particular thing would be stated, though, that there's a limit to volume? I don't see how that could be true, but I'm very intrigued.

194 dB SPL (101.3 kPa) is the maximum theoretical sound pressure level at normal atmospheric air pressure (1 atmosphere = 101.3 kPa). The reason this is the limit is because it's impossible to have a sound pressure greater than the total air pressure.

In a sealed chamber you could increase the total ambient air pressure, but oxygen becomes toxic at 1.6 bar partial pressure (ambient is 0.2 bar). So the maximum SPL you could have in a room where humans could still survive, given a heavily pressurized ordinary mixture of air, is about 212 dB SPL. You could fiddle with the oxygen mix the way deep sea divers do to get a little higher and still live. That's an exercise for the reader

[Brandon B]

The reason this is the limit is because it's impossible to have a sound pressure greater than the total air pressure.

To simplify, shock waves that would make more powerful sound than this blast the atmosphere away, so it is discontinuous and therefore not capable of transmitting sound by the normal definition.

BB

[Chris D]

Cool info. So if you were to take the loudest sound possible, and then put it through a megaphone with powered amplifier, would it just come out as the same volume?