[azryan]

Anyone know of any links to actual scientific human hearing range research?

I know the very general 20Hz-20kHz, but I'm sure that there's much more specific/accurate information than that... but can't find any!

I'm looking for research hopefully showing what's typical, and what's extreme/rare for human hearing range.

Like say.. most people hear up to about 20-25kHz, but some people can hear up to 40kHz.... or pretty much nobody has ever found anyone who can hear anything significant over 25kHz... or whatever the research finds?

Thanks!

I think this would be good info for all of us since there's so much debate now about the high freq. range of DVD-A and SACD, and seems to me like more and more speakers w/ super tweeters or just extended tweeters that reach into a range that it seems no one can hear.

[bob82274]

I wouldn't call this research per se... but it makes for a good story.

I'm studying to become an electrical engineer and am taking my first class in it now.  My professor plays and records guitar so a lot of our electrical stuff involves audio.  He actually brought up SACDs in our class.  I was one of like two people who had ever heard of one much less listen to them on a regular basis.  Anyway we recently had an experiment which involved sampling rates and before that we had tested our hearing (though not in an ideal environment... i could only hear up to around 17kHz due to noise and such).  As he and another professor were deisigning the sampling rate experiment they had a discussion/arugment over what sampling rates they should use.  My professor tested sampling frequencies at 20 and 40 kHz.  He could not hear the difference.  But the other professor couldn't hear the difference between 10 and 20 kHz.  And as such he thought we couldn't either.  Believe me the difference is VERY big.  Well it turns out that they couldn't hear above 12 and 4 kHz respectively.  The 20 kHz was fine for listening to mp3s but it did sound a little flat.  The 10 kHz was like listening to a tin can.  Hurt the ears pretty badly.

[azryan]

Interesting story, but I'm a little confused by some of it...

"-My professor tested sampling frequencies at 20 and 40 kHz. He could not hear the difference."

1) Do you mean sampling rates like 20kHz and 40kHz which only outputs up to 10kHz and 20kHz or...

2) Do you mean your output was 20kHz and 40kHz?

and if it's 2 then are you sure you had a loudspeaker that was flat to 40kHz?

"-The 20 kHz was fine for listening to mp3s but it did sound a little flat."

So you're saying that despite your hearing limit of 17kHz 20kHz sounded flat? or 20kHz sample rate which I'm guessing output info up to 10kHz?

Damn this subject is confusing!

"-The 10 kHz was like listening to a tin can. Hurt the ears pretty badly."

I've never heard MP3's with the high end cropped that much, and I'm sure it'd sound bad, but I'd think it'd sound very 'dull' rather than hurting the ears which usually means 'harsh' sounding -as in too much high end attenuation?

[audiojerry]

bob82274,
future EE, Good for you, my son is a junior in CE (computer engineering), and many of his courses are the same as EE's.

You are putting yourself in the difficult position of learning principles that will tell you that a lot of what you hear as an audiophile can't be true

Best of luck, and I hope your knowledge will be used to for positive contributions to our audio circle.

[nathanm]

Anyone know what frequency television sets put out during normal operation?  I can always tell when a TV set is powered on regardless if it is playing any sound or not.  I guess it is over 12KHz at least.  I always wondered about that.  

Very high frequencies are kind of like very low ones, it's like you can't actually hear the tone but you feel some kind of 'presence'.  Weird.

[azryan]

Nathanm,

"-Very high frequencies are kind of like very low ones, it's like you can't actually hear the tone but you feel some kind of 'presence'.-"

But have you ever heard or felt the presence of something in the upper range that wasn't anything but annoying to you? I never have, while I've (like probably everyone here) has 'felt' subsonic bass that was kick ass to experience.

I've got no answer on the tv hum tone, but I also can 'hear it' when my TV's on. I'd be interested in the answer too. (Probably a good guess saying 12kHz. You based it on the highest sub 20kHz freq. related to the outlet's 60Hz AC right?)

In fact I covered over the green 'on' dot because I didn't need to see it. Then one morning I wake up and find the TV on 'cuz my wife couldn't 'hear' that it was on and thought it was off when she'd just turned the Sat. rec. off! heh

Now the 'on' dot is partly covered so it's 'hardly' visible! heh

When I play a sine sweep that goes up to 20kHz I know I can hear the whole thing and it's 'very clear' when it hits the end. BUT... I don't know if that's because my hearing goes beyond 20kHz, or if I'm hearing a lower harmonic causes by who-knows-what in my audio chain?

I've read that hearing is diff. at diff. volumes, so a low volume hearing test might not be too accurate relating to actual high-ish volume hi-fi listening hearing range??

The A-weighting 'wonky' curve placed on SPL meters to measure a 'flat' system is another wierd thing to me too?
Makes me think there's very little chance of calling any system output 'flat' and being at all accurate??

I dunno?

[nathanm]

Another thing I have always noticed in a sine wave frequency sweep is that after a certain point the tones all start to sound the same.  I am not sure if this is my ears or if distortion in the chain is overwhelming the fundamental.  It's weird.  Judging pitch is really difficult in that range for me.

The TV tone is definitely in the 10th octave I would say.  What frequency it is I am not sure of.

The upper treble presence I described is mainly when listening to pure sines, not necessarily during music.  My friend brought over a function generator once and it was amazing because when we cranked it up around 20KHz+ the SPL meter was reading like 100db but yet we could not hear the sound!  Pretty interesting. Well, there's one example of an instrument being more sensitive than the ear!

[Andrew Lamb]

Today in a lab class, I  attempted to do a quick test on my hearing whiel benching a CVR, now this isn't the best quality recording device by any means, but I was sure it would do the trick.

So, I turned on my audio generator and let it warm up (tubes in these believe it or not), and plugged the generator and the headphones into the test set. I turned up the output voltage until I heard an audible clip, and then turned it down about 5 dB.

I started on a 1 kHz tone, and worked my way down to about 150 Hz where the generator started going a little quiet, and funny sounding. Past about 100 Hz the output was extremely quiet, yet I know my hearing isn't THAT bad yet.

So I proceeded to turn the frequency up, till about 10 kHz, where the same thing happened, mega loss of signal, but I know for a fact that my hearing will go well past this range also. I turn the output voltage up a touch and heard a few harmonics. Cranking the voltage into incredible amounts of clipping I was able to completely obliterate all original signals above 10 kHz, and only receive harmonics on the output... NEAT!

So the conclusion of my test is... I paid outrageous amounts of money for my post secondary education only to receive half assed instruction with sub par equipment... ie, I need a much better generator to further evaluate my own hearing.

I'm sure this is of no value to the post in question, but just thought I'd clear up that it may not be your ears that aren't hearing 25 kHz, it may be the medium used to achieve that... or it may be drunken ramblings, take your pick.