HF Hearing Loss

[Barry]

Often known as a 'mosquito alarm'. Still on the market, but legality debatable.

I have used one of those high frequency mosquito deterrence devices. Don't know what frequency is used but I could hear it - and very annoying it is too.

[Jazid]

If you listen to music you like and introduce a 12kHz low pass filter you will immediately notice the difference, irrespective of your response to a sine wave signal. I'd suspect you would hear the effect of a 15kHz filter as well. I can hear to a bit below 15k, can remember hearing to 20kHz using the Science museum gadget when young, but still want speakers to reach up to 20k.

Our ears have non-linear characteristics and were evolved for a purpose which was not listening to sine waves, more like survival. So these effects should be looked at as interesting characteristics rather than anomalies.

BTW I personally believe I can differentiate a 10kHz sine from a 10kHz square wave, which should not be theoretically possible if I can't hear even the second harmonic. If you try this keep the volume down, hearing damage can still result even if you can't hear anything at all!

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[Sherwood]

If you listen to music you like and introduce a 12kHz low pass filter you will immediately notice the difference, irrespective of your response to a sine wave signal. I'd suspect you would hear the effect of a 15kHz filter as well. I can hear to a bit below 15k, can remember hearing to 20kHz using the Science museum gadget when young, but still want speakers to reach up to 20k.

Our ears have non-linear characteristics and were evolved for a purpose which was not listening to sine waves, more like survival. So these effects should be looked at as interesting characteristics rather than anomalies.

BTW I personally believe I can differentiate a 10kHz sine from a 10kHz square wave, which should not be theoretically possible if I can't hear even the second harmonic. If you try this keep the volume down, hearing damage can still result even if you can't hear anything at all!

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You can try this using this online tone generator which produces square and sine wave tones. I could not hear any difference between the two at 10Khz.

http://www.szynalski.com/tone-generator/

Geoff

[Barry]

https://theartofsound.net/forum/show...+Don%27t+Panic

[Jazid]

You can try this using this online tone generator which produces square and sine wave tones. I could not hear any difference between the two at 10Khz.

http://www.szynalski.com/tone-generator/

Geoff

Not had a scope/sound card on it but I wonder what sampling rate the tones are generated at?

I used an analogue sig genny for my test. To be fair at first I equalised peak amplitudes and in a thread way back on the 'Wam Serge told me I'd screwed up my method. I did try again using equalised power signals and the difference was a lot less, but still audible I thought.

Theoretically if I can't hear 15k then any square wave above 7.5k should sound the same as a sine wave. I've got posher equipment now so if I get a moment I'll try it again

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[Jazid]

Here's the waveforms. As I suggested, it ain't much of a square wave, maybe not different enough to register? IMG_20180921_181839.jpgIMG_20180921_181802.jpg

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[Sherwood]

You can try this using this online tone generator which produces square and sine wave tones. I could not hear any difference between the two at 10Khz.

http://www.szynalski.com/tone-generator/

Geoff

I listened again at 4Khz and I can hear a very clear difference between the Sine and Square wave

[Jazid]

I listened again at 4Khz and I can hear a very clear difference between the Sine and Square wave

It's a very sensitive part of our auditory spectrum so small differences should be easier to discern around this frequency. On top of this we can clearly hear the first and (possibly less clearly) the second harmonics so we really should be able to tell the difference. On top of this I've checked the sine and square at 4kHz and there is an appreciable difference between the amount of energy in the two samples. If I were to hazard a guess did you find the square wave louder? It has higher amplitude and RMS values than the sine, and the waveform is somewhat closer to a square wave and less similar to a sine wave than the 10kHz samples.

I have read that these online signal generators usually display high levels of distortion and noise. This one certainly does.

[Pigmy Pony]

What's the point of good hearing, if what you have between them doesn't work properly?

I've just had a go at a couple of online tests, with my AKG K550's plugged into my laptop. First test did a frequency sweep gradually moving up over the course of a minute, and you were supposed to click the mouse at the point where it becomes inaudible. to be honest, it all sounded a bit quiet, so I turned the sound up and off I went. It became inaudible at about 3.5kz I thought, that can't be good, I'll try another.

The next test included hearing a series of numbers spoken against a noisy background. The conclusion given at the end was that I may have hearing loss, and gave contact details for someone who presumably would charge an arm and a leg for some new ears.

At this point I hadn't heard any music playing (my defence), so when the next test I tried had Rick Astley singing, it was than that I realised that my headphones weren't plugged in properly and all my listening had been from my laptop speakers and through a rather expensive set of ear defenders. I'm not sure if I was relieved by this, or worried.

Anyway, I did the frequency sweep, and it was all a bit strange. Went up to 7.5kz, silence, back at 8kz in right ear only, then both ears from 8.5 to 9.5kz then silence again. Further along I heard a lower frequency tone, getting lower as the tone moved up. Weird. Would that be called harmonics? Maybe it was harmonising with my permanent tinnitus whistle which looks to be at about 3kz.

[Sherwood]

What's the point of good hearing, if what you have between them doesn't work properly?

I've just had a go at a couple of online tests, with my AKG K550's plugged into my laptop. First test did a frequency sweep gradually moving up over the course of a minute, and you were supposed to click the mouse at the point where it becomes inaudible. to be honest, it all sounded a bit quiet, so I turned the sound up and off I went. It became inaudible at about 3.5kz I thought, that can't be good, I'll try another.

The next test included hearing a series of numbers spoken against a noisy background. The conclusion given at the end was that I may have hearing loss, and gave contact details for someone who presumably would charge an arm and a leg for some new ears.

At this point I hadn't heard any music playing (my defence), so when the next test I tried had Rick Astley singing, it was than that I realised that my headphones weren't plugged in properly and all my listening had been from my laptop speakers and through a rather expensive set of ear defenders. I'm not sure if I was relieved by this, or worried.

Anyway, I did the frequency sweep, and it was all a bit strange. Went up to 7.5kz, silence, back at 8kz in right ear only, then both ears from 8.5 to 9.5kz then silence again. Further along I heard a lower frequency tone, getting lower as the tone moved up. Weird. Would that be called harmonics? Maybe it was harmonising with my permanent tinnitus whistle which looks to be at about 3kz.

I think your post highlights that we don't all have 20-20 Khz hearing. I am fortunate in that my hearing is holding up pretty well as I age (better than the rest of me). Having less than perfect hearing does not necessarily reduce our listening pleasure, though it may influence our choice of hardware. Many people are cynical over full range driver speakers since many such drivers have a HF roll off above 15 Khz or even lower. However, if your HF hearing is reduced, does this matter.

I think many people do not have a sense about what a high frequency note sounds like. I am sure that many people would be absolutely shocked as to how high a 10 Khz tone sounds like.

Geoff