Over 22k HZ Gripe-Whats the deal?

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So I have noticed lately that more and more car head unit manufacturers are claiming that they are responsive for 18hz to as much as 28khz.
I understand going below 20 hz because my sense of touch can percieve that signal. But what is the reason for going over 22k...beyond the threshold of human hearing? I cant feel anything.
In fact, not one of my human senses is capable of picking up this signal beyond 22khz. What is the freaking point then?
I have read reputable articles saying that it affects the way we interpret what we hear, but I want to raise the B.S. flag on this industry myth.
At least I think it is a myth unless someone can truly justiy this to me. I mean-If I can't sense it...then it doesn't influence me.
Can anyone here say that a dog whistle has any affect on any of their human sneses?

Anyway, I think that VERY "respected" companies make these claims when it doesn't matter. It's just a sales ploy.
IE: Clarion, Alpine, etc.
My friend recently told me that he bought a clarion because it went around 5KHZ higher than the other head units priced similarly. I just shook my head and laughed at him.

Does anyone else agree that this is B.S.??

Dominick in New Jersey
 
Dominick22 said:
So I have noticed lately that more and more car head unit manufacturers are claiming that they are responsive for 18hz to as much as 28khz.
I understand going below 20 hz because my sense of touch can percieve that signal. But what is the reason for going over 22k...beyond the threshold of human hearing? I cant feel anything.
In fact, not one of my human senses is capable of picking up this signal beyond 22khz. What is the freaking point then?
I have read reputable articles saying that it affects the way we interpret what we hear, but I want to raise the B.S. flag on this industry myth.
At least I think it is a myth unless someone can truly justiy this to me. I mean-If I can't sense it...then it doesn't influence me.
Can anyone here say that a dog whistle has any affect on any of their human sneses?

Anyway, I think that VERY "respected" companies make these claims when it doesn't matter. It's just a sales ploy.
IE: Clarion, Alpine, etc.
My friend recently told me that he bought a clarion because it went around 5KHZ higher than the other head units priced similarly. I just shook my head and laughed at him.

Does anyone else agree that this is B.S.??

Dominick in New Jersey


One word: "Harmonics". What your ears actually hear and what your ears can actually percieve are two different things.
 
It's ******** of the purest ray serene. CDs by definition have nothing abve 22 kHz (really 20 kHz), and FM is band-limited to 15 kHz,
so a head unit going to 28 kHz is kinda pointless.

How do they measure it, anyway? -1 dB, -3 dB, 10 db? I can redefine the same unit as having a top end of 20 kHz, 28 kHz, or 50 kHz with the simple stroke of a pen, merely by changing the above condition.


Cheers,
Francois.
 
Indeed, when talking of radio, tape, cd etc that aren't capable of frequencies considerably higher than 20kHz, the concern is simply that the amplifier should be flat out well past 20kHz to avoid significant phase shift in the audible band.

Now if we want to start talking about some of the more recent source mediums / formats such as 96bit/192kHz that are capable of well in excess of 20kHz then it is an entirely different story.

All of that said, I have serious doubts that any of this would be audible in an auto environment.
 
Audiofreak,

Are you implying that it would be somehow audible in some other kind of environment? This is where I dont get it.

TO-3 is trying to explain this simply with the word "harmonics"?
What is harmonizing if I cant hear it? What difference does it make?

This is kinda like that "If a tree falls in the forest and no one is there" question. Does it make a sound? But I have a better question that relates to this topic.....Does it matter if it makes the sound?LOL-I mean, no hears it either way!

So TO-3, if you could further explain the difference between hear and percieve (In regards to an unknown signal) I would appreciate it.

Your Le Mans explination would imply that if an entire melody was played beyond my human threshold of "hearing", I would still "percieve" something!?

I think this is rubbish.

Thanks to all for the replies

DSP..can you describe the foumula you are talking about regarding the measure...I am not familiar with it. I do understand SPL though...Is it similar?

Dominick in New Jersey
 
Hi Dominick,

If you have a 23 kHz signal, and a 24kHz signal from the same source, and same amplitude, then they will create a harmonic at 1kHz (and also 47kHz) which will be 12dB down on the original signals (NB. no idea of that actual amount of reduction).

If you don't reproduce the original 23 & 24kHz signals, then no harmonic.
 
From the quantative analytical side:http://www.nhk.or.jp/strl/publica/labnote/lab486.html and a qualitative explanation:http://www.acoustics.org/press/150th/Lenhardt.html.
My take:Since I've invested a good bit of change on car audio gear, I'd like it to faithfully reproduce the acoustical information to the speakers. I think the DAC quality is the link, here. The Burr-Brown DAC's do a good job. Another thing to think about is the environment of the soundsage. Noise from my vehicle, wind noise, tire hum, extraneous traffic noise all muddle the frequencies. Is a HU capable of 40khz going to give me a better sound than one that plays to 28khz? I doubt it.
 
Dominick22 said:
Audiofreak,

Are you implying that it would be somehow audible in some other kind of environment? This is where I dont get it.

Yes both are demonstratably audible.

The 2 main phenomena of interest here are:

1. Phase shift in the audible band due to an F3 too close to the audible band. Basically, for real audiophile grade amplifiers, you want the F3 to be no less than 100kHz to minimize phase shift at 20kHz.

2. Combination tones and Difference tones can and do occur within the audible band even if the 2 or more primary tones are outside the audible band. This is really only of particular interest where the source is capable of and actually has valid content outside of the audible range.
 
Hi All,

I just want to ask something quick, anyone who have repaired car amplifiers, might know of this. If you have a smps with a noisy transformer you hear a anoying tweeting sound, I have had it with smps'es that switch over 40kHz, and can still hear it loud and clear... Isn't the freq of that noise proportional to the switching freq?

I'm not a docter, so I don't know what my ears cutoff freq is! 🙂

Anyway manufacturers probabily do it so that your dog with ultra sonic ears can appreciate the capability of your sound system to the max.

Cheers,
Mielie 🙂
 
Dominick22, I'm with you, ultrasonic specs are BS.

The problem with speakers creating a harmonic after a recording, is that if the 23khz and the 24khz created a 1khz harmonic... if the 23 and 24khz were in the original recording, the harmonic would have already been recorded as a 1khz harmonic already.

It is the goal of speakers to create an instantaneous real life representation of what was in the original recording. It is NOT the job of speakers to make up sounds that were not on the original recording, which that harmonic would fall into that category.

I can understand not cutting it off exactly at 20khz, but much above that is silly. I personally can't hear anything past a 17khz sine wave, so YMMV, but it's a huge debate, and it's a huge can of worms.

There are people who trust, and people who question. If you've put yourself in one category, you'll find yourself fighting with the other for your entire life... Here's a good example...

Pot roast in the oven, my sister says "the temperature will rise a tad once you take it out of the oven" I say "no it won't, once you remove the heat energy from an object, it can not get hotter, heat does not have kinetic energy, and there is no exothermic reaction going on after cooking the pot roast for 3 hours." She says "Yes it does."

It's not really worth arguing, get it out of your system.
 
ROTFL:bawling:

Thanks for that supprotive response!

By the way, Have you every discussed with her whether taveling at the speed of light slows time??? OR if a tree falling in the forest with no one there to hear makes a sound???

These might be fun questions at the next family get together!!LOL


Dominick
 
Actually, the problem is that the harmonic occurs in the ear not in the source material. You can create 2 pure sine waves from 2 individual sources and still hear the harmonic. It's alot more complex than what it first appears to be when you get and ear and brain processing involved.

And as for the roast thing, your sister is actually correct, the heat near the surface of the meat will continue to increase the temperature of the meat in the middle for a little while after you remove it from the oven etc.

As always, things are seldom as simple as they first appear.
 
please explain the thermodynamics of a heatsink, getting hotter when the heat source has been removed...

If the harmonic was in the source material when it was created, it will be in the recording.

If it was not in the recording when it was created, it should not be in the recreation of it.
 
I agree that there may be some "lag" per se in an item heating up, but if something has been heated at 300*F for an hour, and the internal temperatures are 210*F internally and 250*F on the exterior. The temperature of the meat will never increase past 250*. However I can understand if the interior moves up to 230* or so to equailbilize. This equilibrium is not "keeping cooking" it's equilibrium.

It's the same as when someone asks you to stand on the corner of 2 streets, maple and branch. Well, Maple and Branch have 4 corners, which corner? How could you stand on a corner of 2 streets? It's impossible. It may be implied that it is one or another, but you can't be on all 4 simultaneously...

assumed and reality are two different things.
 
This is what I don't understand.

If say at the recording studio, a piccolo and an oboe create a 22khz and 23khz frequency sound, then a 1khz frequency harmonic would ensue (or whatever harmonic). If that 1khz frequency would be recorded by the microphone, then there would be no point in recording the 22khz and 23khz frequency.

If you are saying however that the 1khz tone would not be recorded by the microphone, I would have to disagree. If a microphone is a true representation of 20hz - 20khz and harmonics are hearable by a microphone, then there would be no reason to record anything >20khz.

Are harmonics "not real" and only imagined by our ears and brain? I find that hard to believe... where is my logic missing?

Would you agree, that after the heat source is removed from an object, (and no chemical exothermic reactions are taking place) that the temperature can not rise above the temperature it was at when it was being heated?
 
Ocelaris said:
This equilibrium is not "keeping cooking" it's equilibrium.

Yes i agree that it is equilibrium but since the meat in the middle continues to get hotter it does actually get more cooked. An egg is an easy example of this. You can take an egg off the heat when it's still quite runny in the middle and it can become rather solid in the middle if left for a while.

Ocelaris said:
This is what I don't understand.

If say at the recording studio, a piccolo and an oboe create a 22khz and 23khz frequency sound, then a 1khz frequency harmonic would ensue (or whatever harmonic). If that 1khz frequency would be recorded by the microphone, then there would be no point in recording the 22khz and 23khz frequency.

If you are saying however that the 1khz tone would not be recorded by the microphone, I would have to disagree. If a microphone is a true representation of 20hz - 20khz and harmonics are hearable by a microphone, then there would be no reason to record anything >20khz.

Are harmonics "not real" and only imagined by our ears and brain? I find that hard to believe... where is my logic missing?

Would you agree, that after the heat source is removed from an object, (and no chemical exothermic reactions are taking place) that the temperature can not rise above the temperature it was at when it was being heated?

Combination tones and difference tones are not normal harmonics as such. My understanding is that some of it doesn't exist until it meets with our ears and brain.
 
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