14 Apr
2010
14 Apr
'10
7:40 p.m.
Hi,
On Wednesday 14 April 2010 23:17:05 micromoog wrote:
On Wed, Apr 14, 2010 at 3:06 PM, Arnold Krille
<arnold(a)arnoldarts.de> wrote:
I am not into that field of science but as far as I know there is research in
that there are effects when >22kHz frequencies are in a normal sound, it makes
a different effect then when the signal is clipped frequency-wise at 22kHz.
Difference between a violin played inside the room you are and a violin-
recording you hear from CD.
But I don't actually know if that is proven enough or if its voodoo...
Going into psychoacoustics is not really
contradicting the "machines
can't measure it, still it exists". Machines can measure the frequencies
the human
ear can't hear but which still have an effect how we perceive the sound.
Only
the effects aren't looked into as deep as the frequencies below 20kHz
are. To
the result that most scientific research wasn't able to give reliable
results.
Which in turn makes most audio people discard frequencies >22kHz light-
heartedly. And they are right as the scientific (thus neutral) proof of
the effect of the frequencies below 22kHz is _much_ greater then above.
That doesn't deny the psycho-acoustic effects, it only ignores them for
the sake of
bandwidth, reliability and cost...
Sorry to pick on you, but this is the piece of
audio voodoo that irks me
most of all. There is no evidence I'm aware of that supports the idea that
ultrasound has any effect whatsoever on human perception of anything. If you doubt this, as many people do, try the
experiment I used to prove it
to myself:
1) Set up some good synthesizer software (e.g. SuperCollider, csound,
PureData, etc.)
2) Generate pure sine tones of increasing frequency until you reach the
point where you can't hear it (for me this point is just over 16k; for an
older colleague of mine it's just under 14k) (warning: this revelation can
be depressing)
Back-nitpicking: You have to go down with the frequency if you want to test
your upper frequency limit. Otherwise your ear will claim that it hears
something after you actually stopped hearing it. Or switch the frequencies
randomly... Similar to phantom-images in your eyes, your ears can hear
phantom-frequencies...
3) Start cranking up the volume. Your VUs will tell
you it's there . . .
your amp clipping lights will tell you it's there . . . your dog that runs
screaming from the room will tell you it's there . . . your exploding
tweeters will tell you it's there . . . but you won't hear it. Ever.
4) Now that you've got this horrifyingly loud sound blasting throughout the
room, live your life. Watch some TV. Listen to some music. You won't
notice anything. Better yet, have someone else turn it off and on
periodically, and you note when it's on. You won't reliably be able to.
What if you you realize that you feel better with that frequency on?
If its only you out of 100 people, its voodoo. If its 99 out of 100 people,
its a fact proven by science.
Might be I feel better with such a tone around me. Because I don't like dogs
that much. :-P
So . . . if an ungodly pure tone at, say, 18k has no
impact on my senses at
all, ain't *no way* that the "air" of a symphony at 30k will. Until some
unbiased A/B/X tests start showing up that prove otherwise, ultrasound is
pointless in music.
I'd love to be proven wrong here.
Might be you are proven wrong here. As others claimed in this thread, the ear
is not linear (not even logarithmic in every aspect). Might be that 18kHz
don't affect you while 30kHz do:-)
Footnote: Yes, there's a valid argument for higher
than 44.1k when
recording, which involves the filters in A/D converter hardware. There is
no argument for it in the listener space.
Actually I am not defending the "you have to record at 192kHz, everything else
is crap". From my experience, 48kHz is enough. And cheaper on disk-space...
Have fun,
Arnold