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Volume of Headphones

post #1 of 9
6/15/11 at 7:01pm
Thread Starter 
Something I've had on my mind ever since I first heard headphones until now when I finally remembered to post something about it.

So, when headphones are on your head/in your ears, are they really as loud as the perceived volume? For example, if one perceives the volume to be 100db, but takes the headphones off and it's inaudible, is the sound, to the ear, going to do the same damage and such as a 100db sound?

I know listening to music over 90db for over an hour is when it starts to do damage, but is the same true if I listen to music through headphones?

(this may be a really stupid question but as I said it's just something I've always wondered.)
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post #2 of 9
6/15/11 at 7:08pm

If a tree falls in the forest but nobody is around to hear it, does it make a sound?

 

If you think about it on a grand scale, a huge speaker will damage your ears depending on how close you are. same with headphones.... i think.

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post #3 of 9
6/16/11 at 8:53am

A 100dB sound is 100dB, no matter what causes it. I think that is what you are getting at.

 

The tree falling in the forrest still emits sound waves/energy and even if a philospher is not there to hear it, the local squirrel population will and react accordingly. So there is sound.

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post #4 of 9
6/16/11 at 1:22pm

squirrels or birds.

 

Cheers Prog Rock Man. I wasn't sure if I'd explained it properly.

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post #5 of 9
6/17/11 at 7:04am
Quote:
Originally Posted by Prog Rock Man View Post

A 100dB sound is 100dB, no matter what causes it. I think that is what you are getting at.

 

The tree falling in the forrest still emits sound waves/energy and even if a philospher is not there to hear it, the local squirrel population will and react accordingly. So there is sound.

or  you can just put a recorder there and see if there was any sound 
 

 

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post #6 of 9
6/17/11 at 7:36am

When measuring the sound pressure level of headphones you have to make sure that the level meter is close to the headphone drivers and that there is seal - similar to the situation when the headphones are on your head, close to your ears.

 

With increasing distance from the sound source, sound pressure decreases of course (with a 1/r relationship). The azimuth (angle) between sound source and receiver also plays a role (see loudspeaker directivity for example).

 

So if you listen at 100 dB SPL and take the headphones off of your head the sound pressure on your eardrums will drop significantly. The drivers might react a bit differently if there's no seal but they will still produce roughly the same SPL as before.

 

Because speakers are much bigger and more powerful this drop in sound pressure over distance is much smaller. But if 100 dB SPL are measured at / reach your eardrums it doesn't matter what produced it.


Edited by xnor - 6/17/11 at 7:51am
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post #7 of 9
6/23/11 at 1:14pm
Thread Starter 
So it relies on the SPL? Thanks for that.

After posting this and I was away from the internet I realized I could've posted something really simple and gotten my point across much better.

Perceived sound = same damage as real sound?
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post #8 of 9
6/23/11 at 2:01pm

It is not clear to me what you mean with perceived/real sound.

 

It can be very well the case that you think you're not listening very loud with your headphones while, in fact, you are listening much louder than you would with speakers.

But without doing measurements we cannot tell how loud you're listening.

 

 

"dB" is just a logarithmic scale and can be used for anything. When we talk about the level of sound we use dB SPL (= sound pressure level).

If you listen a couple of hours a day you should definitely stay below 85 dB SPL.

 

 


Edited by xnor - 6/23/11 at 2:20pm
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post #9 of 9
6/26/11 at 7:59pm
What is important is the SPL at your eardrums, which is the volume you perceive, anything else is not relevant. Of course, your volume perception is not 100% reliable, it could be influenced by different factors such as alcohol, the presence of physical bass (when you perceived the bass through your body and not just your eardrums...

So when measuring SPL with an SPL meter, it's either at your sitting position with speakers or just a cm away from the driver for headphones (with something to seal the driver).
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