Effects of high frequencies (above 20kHz) on our ears and brain?

[olds1959special]

I remember listening to very high frequencies and not being able to hear them but I definitely felt it in my ears when getting close to the tweeters. AI says "high-frequency sounds (above 20kHz), though inaudible, can activate brain structures and induce physiological and psychological responses known as the "hypersonic effect," including increased cerebral blood flow." Can these high frequency sounds, when part of music or film, add to the psychological impact of the sound? Are there harmonics in playback that present themselves in these high frequency ranges? Is the ability of a speaker to play up to 35 kHz useful or just marketing?

 

[antcollinet]

There has been no valid science to say that it can.

Our ears can't detect it : we can't hear it.

Probably what you felt in the ears was non ultrasonic sound (lower than 20kHz) caused by intermodulation distortion in the tweeter.

 

[JustJones]

Once more Oohashi is resurrected by AI.

 

[sigbergaudio]

I remember listening to very high frequencies and not being able to hear them but I definitely felt it in my ears when getting close to the tweeters.

No you didn't.

AI says "high-frequency sounds (above 20kHz), though inaudible, can activate brain structures and induce physiological and psychological responses known as the "hypersonic effect," including increased cerebral blood flow."

Not scientifically proven to be true in any context relatable to listening to music.

Can these high frequency sounds, when part of music or film, add to the psychological impact of the sound?

No.

Are there harmonics in playback that present themselves in these high frequency ranges? Is the ability of a speaker to play up to 35 kHz useful or just marketing?

Just marketing.



There's an existing 40+ page thread on the subject: https://www.audiosciencereview.com/...dnt-we-upgrade-the-20-20-audible-range.55219/

 

[DVDdoug]

MAYBE they can do something to your brain if they are "super loud".

Or if there are nonlinearities in the playback system you can get intermodulation distortion that causes distortions down in the audible range. That's a reason to filter-out the ultrasonics.

But the harmonics in music (or other normal program material) are weak and the guys who do blind ABX tests have pretty much demonstrated that you can't hear the difference between a high resolution original that contains ultrasonics from a copy down-sampled to "CD quality" (or other low-pass filtering to remove the ultrasonics).

That also means the ultrasonic content doesn't make the listener "feel different" or anything like that because then you could identify "X". ...And there is no fixed time limit in an ABX test so you can listen all day to see how you feel, or if there are any side-effects.

In fact... It turns-out that even if you can hear 20kHz in a hearing test, you won't likely hear the difference if everything above 16kHz is filtered out because those highest-frequency harmonics are weak and usually drowned-out by not-as-high frequencies. Still... We usually like our recordings and equipment to cover the whole audio range.

 

[kemmler3D]

Can these high frequency sounds, when part of music or film, add to the psychological impact of the sound?

It's been claimed they can, but the experiments have not been replicated so most people here consider these claims to be fishy at best.

Are there harmonics in playback that present themselves in these high frequency ranges?

Mostly no. They can exist but the recording and studio engineers need to go out of their way to capture and preserve them. Studio gear isn't usually designed to work beyond 20khz, and since the engineers can't hear that stuff anyway, what you get is what you get. (many times "hi-res" recordings only have noise or artifacts above 20khz)

For the same reasons, musical instruments don't produce a ton of energy in those frequencies either.

Is the ability of a speaker to play up to 35 kHz useful or just marketing?

Depends on how you look at it. A speaker with ultrasonic breakup modes means lower distortion and better directivity in the audible band.

A speaker that does ultrasonic content without a known benefit to audible content is just marketing.

Overall, look at it this way. Take a look at the Fletcher Munson curve and see how the SPL required to hear 20khz shoots up towards the end.

Consider how that line will continue on its upward trajectory with higher frequency, even if you are superhumanly capable of hearing that high.

Then consider the fact that ultrasonic frequencies in music are already naturally much lower in amplitude than lower ones. You would need the ultrasound to be louder than the normal sound just to hear it, but it's much quieter in practice, when it even exists.

So even if there was somehow no upper limit on your hearing, you are still less sensitive up there, and the content is much quieter. Due to masking, You wouldn't really hear much of anything (or anything at all) even if your hearing did technically extend up to 35khz... Which it doesn't.