Am I being paranoid over nothing?... (SPL Level Question)
Oct 2, 2008 at 7:09 AM Thread Starter Post #1 of 7

Ryan41488

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Okay, so with my crappy Skullcandy's came a little piece of paper on SPL's/Noise Induced Hearing Loss. After looking at it, I'm a little concerned, seeing as how the SC's have a SPL of 100db which I guess, is fine, and my Creative EP 630's which I've been using since they sound better and aren't bass bloated that ruins everything like the SC's have a SPL of 106. That said, I'm someone who likes to listen to my iPod a lot. My volume when using the EP's is down all the way to where the blue bar isn't even showing anymore, still though, in the back of my head..I fear it'll still damage my hearing. I like the EP's because they have a nice freq response of 6 hz - 23 hz (or 20), which to me sounds a lot better than 20 - 20, as the SC's are just blah. But, at the same time I like the SC's because the SPL is down 6 notches..I know it won't do much..but..am I being paranoid over nothing?..I wouldn't mind getting a pair of earbuds with a lower SPL, I just don't know where to find them, so if anybody could help me on that I'd be happy. My ENT also noticed some fluid behind my eardrum, I'm not sure if listening to earphones with a high SPL is a good idea with that or not, but, I figured I'd ask here, as I just don't want to damage my hearing. =/
 
Oct 2, 2008 at 8:17 AM Post #2 of 7
That stat is for maximum SPL that the units are capable of producing. If you're not listening at maximum possible volume (and sounds like you listen at very quiet listening levels indeed), then you have nothing to worry about.
 
Oct 2, 2008 at 8:56 AM Post #3 of 7
Ryan, you have a LOT of misconception about reading spec and hearing damage in general.

First, SPL rating listed on the spec is usually measured as the peak SPL @ 1kHz with 1mW of power (= a specific setting). It doesn't mean the headphone will constantly pump out that SPL all the time. When you reduce the volume on your iPod, you limit the power to the headphone and reduce the SPL of the headphone. The lower the volume setting, the lower the SPL. You can have a 106dB listed headphone pumping out 100dB SPL of sound doing more damage than a 120dB listed headphone pumping out 90dB SPL of sound. It is the volume you listen to that matter, not the SPL spec. As long as you listen to music in low volume, SPL rating doesn't really matter to your hearing.

Second, most commercially available music in either CD, non-specific-mentioned lossless or lossy format online are capped by the manufactures (aka. the big music label) to be 20Hz ~ 20kHz (CD's Red book Standard). It won't help if you have headphone up to 35kHz when the music you are playing doesn't content any data over 20kHz. More of, almost all currently available DAP, including iPod, doesn't have DAC inside good enough for music beyond 16bits encoding (= another cap on 20kHz). In simpler term, all the music you download from iTune don't have any data over 20kHz. If you want to listen to your music that does have data over 20kHz, you need to invest in either SACD, DVD-A, or old fashion analog recording.

Third, spec are usually very misleading. Frequency response are suppose to be measured with a tolerance value, to inform the reader how accurate the freq. resp. is. Unfortunately, most headphone manufacturers would rather not list their actual tolerance value because it limits the actual range of freq. resp. that can be listed. For example, if you look at the following freq. resp.: With + 3dB tolerance, the spec should be listed at 170Hz. However, with + 9dB tolerance, the spec becomes 120Hz. With out tolerance value, you can listed bass as low as 20Hz, but it will be something like -40dB. Assuming the spec is measured at 90dB SPL, -40 dB will be 90-40 = 50dB(SPL). The 20Hz bass is so low (50dB), it is pretty much unnoticeable in 90dB of music. That is why manufacturers don't like to list the tolerance value - so people who don't know how to read the spec will be impressed by a headphone that goes as low as 10Hz without realizing it is all marketing trick.
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Oct 2, 2008 at 10:11 AM Post #4 of 7
Quote:

Originally Posted by Ryan41488 /img/forum/go_quote.gif
My ENT also noticed some fluid behind my eardrum, I'm not sure if listening to earphones with a high SPL is a good idea with that or not, but, I figured I'd ask here, as I just don't want to damage my hearing. =/


I would ask your ENT doctor about that, if I were you, he'll probably be able to give you better advice and just tell you not to listen to loud music
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ClieOS is right, though, SPL stands for Sound Pressure Level and it's literally a measure of the pressure differential at a given point and will get lower the further away from the source you are. I won't go into the maths of it but basically, if you consider the physics, the higher the pressure differential, the more your eardrum will move and the louder it sounds. So you're right, higher SPL is worse but as ClieOS said, SPL is a function of volume. Theoretically if you have a pair of earbuds that can produce 200dB and a pair that can produce 100dB, when you're listening to them, if the volume sounds the same, the SPL at your eardrum will be the same..

Unless your iPod is broken/heavily modified, if you're listening at volumes that low you have NOTHING to worry about. Also, as ClieOS said, these headphone manufacurers can claim pretty much anything and give you "specs" to back it up. They don't detail their testing procedures so I wouldn't take their specs as gospel if I were you..

Just for reference, if I remember my high school physics, standing 100m from a jet engine, the SPL is about 110dB (in air) so if you reckon you could hear a jet engine 100m away from you while you're listening to your tunes, you're prolly not pumping 100dB of noise into your head
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Hope I helped.
 
Oct 2, 2008 at 7:03 PM Post #5 of 7
Thanks for all the help
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, so it doesn't matter how long I listen to my iPod then?..And as far as the stuff on that paper goes, they same the same crap on the Osha website when it comes to Noise Induced Hearing Loss..I believe it was, listen to a SPL of something something something, 3 times a week, at 2 hours, will affect your hearing in the future, etc, etc, or, something of the sort
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Oct 2, 2008 at 7:58 PM Post #6 of 7
Of course it matters how long you listen to your iPod!!!!! (unless you listen at inaudible volumes, but I guess you would agree that that's a bit pointless)
 
Oct 3, 2008 at 8:45 AM Post #7 of 7
Quote:

Originally Posted by Ryan41488 /img/forum/go_quote.gif
Thanks for all the help
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, so it doesn't matter how long I listen to my iPod then?..And as far as the stuff on that paper goes, they same the same crap on the Osha website when it comes to Noise Induced Hearing Loss..I believe it was, listen to a SPL of something something something, 3 times a week, at 2 hours, will affect your hearing in the future, etc, etc, or, something of the sort
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If you're listening at levels that low, no, it doesn't matter how long you listen to your iPod. You need to be exposed to about 85dB for prolonged periods of time to damage your hearing, which is like standing 10m away from a really busy road. You said you had your iPod on so low you could barely see the blue volume bar, well, I wouldn't worry about it then because that is going to be FAR lower than 85dB. If you keep the volumes reasonable, you won't have any problems. I like listening to loud music occasionally, everyone does and our ears can take it for short periods of time but don't overdo it
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