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Comment by Synaesthesia | Hacker News Reader

Almost nobody hears beyond 16kHz, from testing I've done, and I don't think the musical content above that freq is really useful.

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Correct, but a filter that's flat to 16kHz with an abrupt cut-off above 16kHz would introduce a lot of noise and artifacts, especially with 80's tech.

Filters with a gradual roll-off are much smoother, cleaner and cheaper. 44 kHz allows a filter with only 20dB roll off starting at ~16kHz to be used instead.

Filters are necessary because if you digitize something at 44kHz, any noise above 22kHz becomes noise at a frequency < 22kHz, aka audible.

Have you done any testing with teens or children? I could hear all the way to 23 kHz in my early 20s. Now at 32 I only hear up to 16 kHz (well I can hear a slight tone at 17 kHz but it's very slight).

That's not true for me, I can hear higher frequencies just fine. It can cause problems sometimes! Besides the usual annoyances like transformers in old CRTs, there's a video game whose soundtrack has these horrible piercing tones left in, and I've only found a few other people complaining about it online. Most—including the composer, I assume—can't hear them, so are unbothered.

I can hear that. Helps noticing neon lights go bad

Yeah nobody hears 16khz sine waves. But those high frequencies also make low frequency transients (eg square edges)sharper, and reduce ringing.

But if someone can't hear a high enough sine wave, doesn't that mean the same thing as they can't perceive the sharpness of transients with frequency components above their hearing limit? Surely if you can't hear a frequency when presented as a high-intensity constant sine wave, you're not going to hear it when mixed in with all the other frequencies for a short moment in the form of a step or impulse. Those hairs in the inner ear aren't going to activate, in other words (or their signal won't get through).

I am not an expert on this but my suspicion is that human ear is not a linear time invariant system and thus it does not make sense to place a hard cutoff at some frequency over which you can not hear. The response might change wrt to the spectral content of the overall sound.

I can hear 16khz sine waves when played on their own. ¯\_(ツ)_/¯

That's nice, try to conserve it and be careful with your ears. Most adults have already lost enough of their hearing that they can't even hear if an old style CRT based TV is on (which is in the EU 15625 Hz). By the ripe old age of 50 you're lucky to get 10 KHz and when you are at 70 it will be much less than that still. Babies and dogs can hear ridiculously good. The highest note on a piano is still below 5 KHz.

Handy resource:

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

Note that higher frequencies are very directional and you may have to move your head around a bit to catch the tone, this works best by finding something you just can't hear and then to move your head around to see if you really can't hear it or if you only can't hear it from that particular direction.

I'm 53 and I can still hear the NTSC 15.734KHz whine of a CRT, although it's not nearly as obvious as it was in my 20s. I also suspect there are some "dead" spots in my hearing in the 13Khz-15Khz range but it picks back up from there for a bit.

You're very lucky! In my early 40's I could still hear it but now I really can't, the cutoff is below 10 KHz already. But tinnitus doesn't help, it tends to reduce your hearing sensitivity overall.

I've got a strong tinnitus, but I still hear up to about 14Khz (I'm 53). In fact the tinnitus is all those frequencies up to 21Khz I used to hear and don't anymore, ringing in full in my ears...

Tinnitus is a collection of different symptoms, you can have various forms of it, for instance where you hear a continuous ringing in the background, where certain frequencies get dampened or amplified and so on. It's quite an interesting phenomenon. 14Khz at 53 is very nice!

Also I know that my medication plays a role in my tinnitus -- I switched for a while, and my tinnitus went down notably; unfortunately with the other medication I had tachycardia, which is worse than tinnitus...

I can pretty distinctly hear 18kHz sine waves and so can many of my friends, I don't think it's that rare.

If you actually weren't able to hear past 16kHz you wouldn't be able to hear the ringing caused by a good filter above 16kHz, and you wouldn't be able to tell a difference in the transients either.

Defffffffinitely did not just hurt my ears playing really loud 16,220 Hz sine waves to prove someone on the Internet wrong.

I got up to 21kHz and then either I stopped being able to hear things or my speakers crapped out, not sure. On an unrelated note, those frequencies are annoying

Fun fact: most "maximum frequency humans can hear" numbers are not actually "maximum frequency humans can hear" but rather where the threshold of hearing (minimum volume level you can hear) crosses the threshold of pain (minimum volume level that is painful).

When I started my career I could hear 15,625hz (the line rate of the CRTs in a PAL environment). I can't now, and not just because those CRTs no longer exist.

Alas I can still hear 1khz.

Seems to be true. When I was younger (in my 20's) I used to be able to hear CRT whines which I guess is in the 15khz range.

Less so now, which is too bad. I recall there being specific TV's which I found the whine really soothing while watching stuff. Computer monitors I never heard the whine which is up around 31khz according to some guys on Reddit.

Not listening to much Sachiko M?

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