[Anton K.]

There has been a lot of hype recently about new audio formats (SACD and DVD-A).
Many manufacturers proudly say that  "our amp has range from 2 to 200,000 hz so it is dvd-a ready", and we many speakers' response is flat up to 25000 hz.
Yet it is wellknown fact that most males can only hear 17000 hz at best.
Then some claim that, yes, those sounds we can not hear but we can certainly "feel them".
Has anybody compared sound of speakers which go up to 20000 hz with those which can play as high as 25000 (the source/amp being the same)?
Has anyone "felt" those ultra-high sounds?
I think i have once. It was when I caught a bat (seriously). I held it in my hand and it cryed right into my face. At first i could hear some very high sounds, but then those sounds vanished, though the bat kept opening its mouth. It felt like the bat "switched over" to ultra-sound register, and felt kindof headache. If this is what SACD combined with supertweeters does, then, thanks, I'll pass.
So, now YOUR listening impressions (and not too much tech-talk, please)?

Anton

[aaird]

I have a friend who claims he can hear a dog whistle and nobody else in his family can.  

I am not sure you can feel a sound with that short of a wavelength, but hey, I am nowhere close to an expert.  Stranger things have happened.

Andrew

 

[nathanm]

Wow, a bat catcher!  You must have some quick reflexes!

Ultra-high frequencies are kinda hard to describe - I don't know if 'feel' or 'hear' are the right words, but you almost 'sense' them without really knowing how you are doing it.  Although I think the fact that you are expecting to be in the presense of ultrasonics is also a factor.  It's probably similar to infrasonics in that we experience them in a way that may not be immediately apparent.

[ehider]

I have an audiophile buddy that talked about days of yore when his band's amplifiers could over occilate. These amps could producing SIZABLE bursts of energy above 20khz through his speaker stacks which had piezo tweeters (those tweeters can easily play frequencies way above 20khz). He swears this made his and others eyes water when they got close to the amplifier stack!

Since this experience, he did a/b tests where he would listen to his audiophile system in the dark with and without small goggles. Since he had a large selection of master tapes, he used his pro gear as his front end many times. Knowing that his audiophile speakers also had ultra high frequency capabilities (-3db down at 35khz) and his front end could easily produce harmonics above 20khz, he wanted to "see" if covering his eyes would change the perceived sound. His experiments showed that certain songs had a foreshortening of depth with goggles on. He could have easily just opened and closed his eyes, but he feels that using these muscles slightly changed the tension on his face, which in turn could slightly affect the way his ears would capture and process various sounds.

He did say that the "covering your eyes" experiment was NOT audible with cd players in his audiophile system. BUT, he swears that he does hear more depth when he keeps his eyes open (versus being covered) with his turntable rig!. Perhaps his analog rig's electronics can easily produce overtones above 20khz.?

I have no reason to doubt his results regarding keeping your eyes open when listening to an electronic source that can play above 20khz. This guy is veeeeeeery anal when it comes to doing experiments!

[BlackCat]

There ain't gonna be anything on a CD above 22KHz.  That's 'cause they use a 44KHz sampling rate, the Nyquist theorem dictates that 22Khz is as high as you're gonna get.

[KevinW]

Bandwidth above 20 kHz is important for sound quality.  However it's not a question of whether humans can hear sounds above 20 kHz.  Human ears can't and most people really only hear below 15-17 kHz anyway.  Some people will argue that the humans still somehow can detect ultrasonics and will provide research that suggests this, but I haven't investigated this research personally and cannot speak authoritatively about it.

Where bandwidth above 20 kHz is important for audio is in phase shifts.  When you roll off a signal, any signal, from any kind of rolloff, phase shifts occur beneath the rolled-off point.  Human ears can EASILY detect those phase shifts in music, although some people are better at this then others, and it also takes some practice (like developing a taste for beer or wine).

The further out of the audible range for the rolloff (aka a "pole" in engineering terms), the lower the audible phase shift will be.  This is the primary reason behind why a wide bandwidth is actually a useful spec for determining sound quality on paper.  It's not the last word on SQ, by any means, but it is indicative of a good design.

Also, the shape of the "pole" siginificantly effects the amount of phase shift.  In general, faster rolloffs have an exaggerated effect. For example, in speakers, 1st order slope crossovers tend to sound better than 4th order slopes.  They are more musical, as the ear doesn't detect phase shift anomalies as much.  This is one of the tradeoffs that needs to be made in speaker design...  Sometimes higher slopes sound better because of the necessity of steeper slopes to control drivers that are forced to work close to the limits of their linear operating range.

[_scotty_]

There has been a lot of hype recently about new audio formats (SACD and DVD-A).
Many manufacturers proudly say that  "our amp has range from 2 to 200,000 hz so it is dvd-a ready", and we many speakers' response is flat up to 25000 hz.
Yet it is wellknown fact that most males can only hear 17000 hz at best.
Then some claim that, yes, those sounds we can not hear but we can certainly "feel them".
Has anybody compared sound of speakers which go up to 20000 hz with those which can play as high as 25000 (the ...

 Ultrasonics have been used to keep people away from places you would rather not have them be for quite some time.Frequencies between 25kHz and 35kHz at 95 to 105 db emitted by piezo-electric ultrasonic transducers
are very effective at repelling people and animals from an covered by the
sonic field. People will avoid the area and not know why. Continued exposure to the ultrasonic field will make people edgy, nervous,and irritable for no reason that they are consciously aware of.

[nathanm]

Continued exposure to the ultrasonic field will make people edgy, nervous,and irritable for no reason that they are consciously aware of.

Just like Muzak!  (not a joke)

[jqp]

I have heard that the way to listen to music most effectively is with your mouth slightly open.

Though your eardrums are at the ends of your ear canals, they and the inner ear are surely affected by sound traveling into the head via many paths. Mouth, sinuses, eye sockets, etc.

So here is the best way...

30 minutes after ingesting caffeinated drinks, gargle with warm salt water for 30 seconds. (Save the gargled water, you will use it later). Sit with both feet on the floor, get rid of all ions in the air, breath 40% through the mouth, 60% through the nose...

Seriously, I would ask myself how high the frequencies are in a symphony hall, and attempt to allow for them. At least as a start. In the studio you can create sounds that should never be created...

Also about the bat - certain sounds can make the muscles in your ears tighten up, maybe also your eye muscles. That could probably cause a headache.