What is the advantage on high-sampling rate ?

danlavry@mindspring.com (dan lavry) writes:

> I agree with you, and 88.2KHz and 96KHz are certainly fast enough, an
> overkill in fact.
> 
> The argument that filtering near 20KHz while at 44.1KHz is true, but
> going to 88-96KHz solve it. In fact, while douing that (going faster),
> the ability to work nera zero (say 20Hz or other low frequencies)
> takes gets tougher. So 96KHz is ok with me. 192KHz is not.
> 
> BR
> Dan Lavry

I agree. That's why I proposed a 64/32 scheme awhile back. 64 kHz -
enough room for those folks who have the hearing of a bat and to let
the antialias filters breathe - and 32 bits - which covers the range
from the energy of a flea fart in Kenya to the total energy of the
universe.

Of course it's a "pipe scheme" - not likely to be adopted. But it
seems reasonable to give some thought to these matters.
-- 
Randy Yates
Sony Ericsson Mobile Communications
Research Triangle Park, NC, USA
randy.yates@sonyericsson.com, 919-472-1124

Randy Yates wrote:

> and 32 bits - which covers the range
> from the energy of a flea fart in Kenya to the total energy of the
> universe.

That was a figure of speech, right?   I mean, there are 10^77
atoms in the known universe -- whatever is tangible for us would
be in the order of 10^23;  that leaves a range of 10^54;  you
would need approximately 180 bits to cover the dynamic range
of the energy in 10^23 molecules to the total energy of the
universe.

Please tell me that you were joking and that I just wasted my
time on doing those calculations!  :-)

Carlos
--

Carlos Moreno wrote:

> Randy Yates wrote:
> 
>> and 32 bits - which covers the range
>> from the energy of a flea fart in Kenya to the total energy of the
>> universe.
> 
> 
> That was a figure of speech, right?   I mean, there are 10^77
> atoms in the known universe -- whatever is tangible for us would
> be in the order of 10^23;  that leaves a range of 10^54;  you
> would need approximately 180 bits to cover the dynamic range
> of the energy in 10^23 molecules to the total energy of the
> universe.
> 
> Please tell me that you were joking and that I just wasted my
> time on doing those calculations!  :-)
> 
> Carlos
> -- 

That was hyperbole. You didn't waste your time, you educated yourself
and the rest of your readers.

Jerry
-- 
Engineering is the art of making what you want from things you can get.
�����������������������������������������������������������������������

"Arthur" <arthurc99@yahoo.com> wrote in message news:<c65haq$1dgf$1@news.hgc.com.hk>...
> Hello all,
> 
> Recently, there is a tendency to use high sampling rate 96 KHz, 192 KHz in
> the audio application.  To my knowledge, about ~ 20 KHz, everything will be
> cut off from the loudspeaker, amplifier, etc..  So, why 96 KHz, 192 KHz
> instead of 48 KHz..
> 
> Regards
> Arthur

Well, I suspect that it helps the manufacturers sell more equipment.

Think of it as a form of "trickle-down", why don't you?

Hey, Dan, man, what do you think of this one?

http://www.omigaaudio.co.uk/Services.htm

or this:

http://users.informatik.haw-hamburg...r/MP3-risk.html

Erik de Castro Lopo wrote:
> Arny Krueger wrote:
>>
>>> There have also been double blind tests which prove that even
>>> untrained listeners can tell the difference between a 10kHz sine
>>> wave and a 10kHz square wave (components at 10kHz, 30kHz, 5okHz
>>> etc) even after the two signals have been normalised to have the
>>> same perceived volume.
>>
>> I'd like to see a formal cite for that. This is not a very tough
>> listening test to do, and IME it always comes out negative.

> I have only seen second hand references to this study, but I believe
> the original is this one:

>    Tsutomi Oohashi, Emi Nishina, Norie Kawai, Yoshitaka Fawamoto,  Hiroshi
Imai
>    "High Frequency Sound Above the Audible Range Affect Brain Activity
>    and Sound Perception."
>    Audio Engineering Society preprint No 3207 (91st convention, NYC)

This study is well-known to be flawed because there were differences in
response in the  systems being compared, below 20 KHz.

The paper also does not mention square waves, so it is not a proper response
to the question that was asked.

The paper was retreaded and the discussion moved to a less-rigorous (in
terms of audio technology) discipline and can be found here:

http://jn.physiology.org/cgi/reprint/83/6/3548.pdf

Still doesn't mention square waves.

Randy Yates wrote:

> Oh, that. Yep, they convinced me. The other 4 billion people on the
> planet must be wrong. They must have discovered something that no
> other researcher has been able to find. Yessirr, that's a taker. 

Yeah, but what if I revert the question?

What is the spectrum, up to -120dB, of a violin, used
with some reasonable score?

I mean, if the violin has some energy up to 100KHz, for
example (I've no clue of reality, in this case), then it
would make sense to claim "Hi-Fi" only a system that can
reproduce that, all the rest is just an approximation,
independently from human perception capabilities (you never
know what kind of non-linearities can happen...).

bye,

-- 
   Piergiorgio Sartor

Piergiorgio Sartor <piergiorgio.sartor@nexgo.REMOVE.THIS.de> writes:
> [...]
> independently from human perception capabilities 

Right. And we should start extending LCDs, CRTs, and other
display devices to ultraviolet - you never know what the
eye might do with those high frequencies. 
-- 
%  Randy Yates                  % "So now it's getting late,
%% Fuquay-Varina, NC            %    and those who hesitate
%%% 919-577-9882                %    got no one..."
%%%% <yates@ieee.org>           % 'Waterfall', *Face The Music*, ELO
http://home.earthlink.net/~yatescr

On Wed, 21 Apr 2004 17:27:34 -0400, Carlos Moreno
<moreno_at_mochima_dot_com@xx.xxx> wrote:

>Jon Harris wrote:
>
>> I often think about the waste in using conventional audio CDs for "books on
>> tape".  A book often requires many CDs, maybe even dozens.  You end up with a
>> mono source with fairly limited dynamic range and frequency content being
>> recorded onto a stereo, 16-bit, 44.1kHz medium.  You could increase your
>> playback time by at least a factor of 4 just by switching to mono/22kHz, which
>> would be very adequate for the task. 
>
>Ha!  Not if the audio book is read by, say, Gillian Anderson;
>you definitely don't want to miss a single Hz from her original
>voice's bandwith!  :-)
>
>Carlos

I agree completely.

Carlos, did you see the extraordinary photos 
of our Beloved Dana Scully at:

http://www.gillian-anderson.co.uk/allure_images.html

Now there's the kinda girl you'd like to 
bring home to meet your parents.

[-Rick-]

Piergiorgio Sartor wrote:

> Randy Yates wrote:

>> Oh, that. Yep, they convinced me. The other 4 billion people on the
>> planet must be wrong. They must have discovered something that no
>> other researcher has been able to find. Yessirr, that's a taker.

> Yeah, but what if I revert the question?

> What is the spectrum, up to -120dB, of a violin, used
> with some reasonable score?

The spectral content of *any* musical instrument is irrelevant to the basic
question, which is audibility.

You can transmit anything you want to, but if the receiver doesn't respond
to it, then your transmissions are futile.

> I mean, if the violin has some energy up to 100KHz,

It does, but you also need to quantify that energy unless you don't believe
in the concept of amplitude thresholds for hearing.

>for  example (I've no clue of reality, in this case), then it
> would make sense to claim "Hi-Fi" only a system that can
> reproduce that, all the rest is just an approximation,
> independently from human perception capabilities (you never
> know what kind of non-linearities can happen...).

In fact you can know what kind of non-linerities can happen, but again
system nonlinearities are irrelevant to the basic question of the perceptual
limitations of humans.

If you've got the mics, you can find musical instruments with measurable
output at 10 MHz and beyond.

Acoustical generators (e.g. musical instruments) don't just stop producing
sound at some given frequency. At the least, their output slopes down at 6
or 12 dB per octave. So, this approach is a very long slippery slope.

Back in the real world, just about everybody in the Western world carries an
excellent generator of high-frequency and ultrasonic sound around in their
pocket. It's called a keychain.

I've measured a number of keychains and they tend to perform in a similar
fashion, so the one in your pocket won't perform that dissimilarly form the
one in my pocket. The keychain is one of the most convenient generators of
exceptionally rich high-frequency sounds around. It's been used for at
casual audio testing literally for decades.

You can find a picture of the spectrum of an audios sample taken from my
keychain at:

http://www.pcabx.com/technical/sample_rates/index.htm  figure 5 and figure
6.

Convinced of the richness of its high frequency audio content?

If so, then do YOUR OWN  DBTs with the provided software and data file, and
a computer with a 24/96 audio interface and the speakers or headphones of
your choice.  24/96 and even 24/192 audio interfaces are now plentiful and
relatively inexpensive. The M-Audio "Revolution 7.1" is a good card to use
as is their "Audiophile 24/96" or Echo's Mia. The SoundBlaster Audigy stuff
tends to be so flawed (high frequency IM) as to be questionable for this
application.

If you don't trust my files, analyze them to double-check my work, or even
make some for yourself. This is not rocket science, it's just a walk in the
park for people who even know just a little bit about audio production.

It's safe to predict that you'll sing at least a slightly different tune
after you get your hands dirty with the real world!