Around the end of 2003, on a thread called 384KHz (regarding fast sampling),
I promised to post an artical on sampling with some focus regarding the
ridiculess 384KHz and 192KHz trend.
It took some work, and it is a long paper. If interested, go to
www.lavryengineering.com
Click on support, and it is the first artical under "white papers". It is
called "Sampling Theory".
It is a pdf artical and can be downloaded and printed, but the plots are in
color (and I do refer to the colors), so color printer is better.
Or, if you rather not stay connected, you can download it and view on the
screen...

The artical is educational, but it is not just "old rehash". Some of the
material aproaches things from "different angles", though all within the
bounds of science and engineering.

best regards to all

Dan Lavry

In article ,
(dan lavry) wrote:

Around the end of 2003, on a thread called 384KHz (regarding fast sampling),
I promised to post an artical on sampling with some focus regarding the
ridiculess 384KHz and 192KHz trend.
It took some work, and it is a long paper. If interested, go to
www.lavryengineering.com
Click on support, and it is the first artical under "white papers". It is
called "Sampling Theory".
It is a pdf artical and can be downloaded and printed, but the plots are in
color (and I do refer to the colors), so color printer is better.
Or, if you rather not stay connected, you can download it and view on the
screen...

The artical is educational, but it is not just "old rehash". Some of the
material aproaches things from "different angles", though all within the
bounds of science and engineering.

best regards to all

Dan Lavry

Dan, it appears that your ISP is having problems. I get a redirect to
fatcow.com saying that the page does not exist.

"dan lavry" wrote in message
om...
Around the end of 2003, on a thread called 384KHz (regarding fast
sampling),
I promised to post an artical on sampling with some focus regarding the
ridiculess 384KHz and 192KHz trend.
It took some work, and it is a long paper. If interested, go to
www.lavryengineering.com
Click on support, and it is the first artical under "white papers". It is
called "Sampling Theory".
It is a pdf artical and can be downloaded and printed, but the plots are
in
color (and I do refer to the colors), so color printer is better.
Or, if you rather not stay connected, you can download it and view on the
screen...


Thanks

jb

In rec.audio.pro, (Ralph & Diane Barone) wrote:

Dan, it appears that your ISP is having problems. I get a redirect to
fatcow.com saying that the page does not exist.

Do you have flash disabled or not installed at all? I have my
browser set to "do you want to run such-and-such?" and I usually say
no and get to the text I want to read anyway. When I say no on this
site, it goes to a download-flash-or-click-here-to-enter page, and if
I "click here to enter" and again say no it goes to the fatcow 404
page. But things work fine if i say yes to the "A script is
accessing..." prompts.
This should be a shortcut to the article without having to go
through the flash website:

http://www.lavryengineering.com/docu...ing_Theory.pdf

I hope it's okay with Larry that I post the link, but then I hear
it's always easier to ask for forgiveness than for permission.

-----
http://mindspring.com/~benbradley

dan lavry wrote:

If interested, go to
www.lavryengineering.com

If interested? Are you kidding? :-)

Excellent piece of work, Dan. I would make one suggestion.
At the point where you introduce the sinc() it would be
good to motivate that by saying that the sinc() is the
result of a filter acting on a real impulse that is
infinitessimally short where that filter is a perfect
lowpass, giving output equal to input for all frequencies
below 1/2 the sample rate and zero for all frequencies above it.

I'm sure you can find a better way to state it but I think
it's important that people understand why you are using it.


Bob
--

"Things should be described as simply as possible, but no
simpler."

A. Einstein

(dan lavry) writes:
It took some work, and it is a long paper. If interested, go to
www.lavryengineering.com
Click on support, and it is the first artical under "white papers". It is
called "Sampling Theory".
It is a pdf artical and can be downloaded and printed, but the plots are in
color (and I do refer to the colors), so color printer is better.
Or, if you rather not stay connected, you can download it and view on the
screen...

Can you post a direct url to the paper? When I view
www.lavryengineering.com, I get a flash detection page,
and the link to bypass flash gets a 404 error. Thanks.

"Paul Rubin" wrote in message
...

Can you post a direct url to the paper? When I view
www.lavryengineering.com, I get a flash detection page,
and the link to bypass flash gets a 404 error. Thanks.

I just get a black screen!

TonyP.

Paul Rubin wrote:
(dan lavry) writes:
It took some work, and it is a long paper. If interested, go to
www.lavryengineering.com
Click on support, and it is the first artical under "white papers".
It is called "Sampling Theory".
It is a pdf artical and can be downloaded and printed, but the plots
are in color (and I do refer to the colors), so color printer is
better. Or, if you rather not stay connected, you can download it
and view on the screen...

Can you post a direct url to the paper? When I view
www.lavryengineering.com, I get a flash detection page,
and the link to bypass flash gets a 404 error. Thanks.

http://www.lavryengineering.com/docu...ing_Theory.pdf

In article ,
Ben Bradley wrote:

In rec.audio.pro, (Ralph & Diane Barone) wrote:

Dan, it appears that your ISP is having problems. I get a redirect to
fatcow.com saying that the page does not exist.

Do you have flash disabled or not installed at all? I have my
browser set to "do you want to run such-and-such?" and I usually say
no and get to the text I want to read anyway. When I say no on this
site, it goes to a download-flash-or-click-here-to-enter page, and if
I "click here to enter" and again say no it goes to the fatcow 404
page. But things work fine if i say yes to the "A script is
accessing..." prompts.
This should be a shortcut to the article without having to go
through the flash website:

http://www.lavryengineering.com/docu...ing_Theory.pdf

I hope it's okay with Larry that I post the link, but then I hear
it's always easier to ask for forgiveness than for permission.

-----
http://mindspring.com/~benbradley

That was the problem Ben. Thanks.

Arny,

http://www.lavryengineering.com/docu...ing_Theory.pdf

Thanks very much for doing that.

I too have my Internet options set to Prompt, and I refuse to run ActiveX
nonsense on my computer.

--Ethan

In rec.audio.pro, (Ralph & Diane Barone) wrote:

In article ,
Ben Bradley wrote:

...

http://www.lavryengineering.com/docu...ing_Theory.pdf

I hope it's okay with Larry that I post the link, but then I hear
it's always easier to ask for forgiveness than for permission.

-----
http://mindspring.com/~benbradley

That was the problem Ben. Thanks.

You're welcome. Now I only need to apologize to Dan Lavry for
calling him Larry.

-----
http://mindspring.com/~benbradley

"Ben Bradley" wrote in message
...
In rec.audio.pro, (Ralph & Diane Barone) wrote:

In article ,
Ben Bradley wrote:

...

http://www.lavryengineering.com/docu...ing_Theory.pdf

I hope it's okay with Larry that I post the link, but then I hear
it's always easier to ask for forgiveness than for permission.

-----
http://mindspring.com/~benbradley

That was the problem Ben. Thanks.

You're welcome. Now I only need to apologize to Dan Lavry for
calling him Larry.

Larry Lavry - that's his evil twin brother who insists that EVERYTHING must
be recorded above 192khz!

Seriously though, Dan; that was very interesting stuff - thanks for
posting it.
--


Neil Henderson
Progressive Rock
http://www.saqqararecords.com

In article ,
(dan lavry) wrote:

Around the end of 2003, on a thread called 384KHz (regarding fast sampling),
I promised to post an artical on sampling with some focus regarding the
ridiculess 384KHz and 192KHz trend.
It took some work, and it is a long paper. If interested, go to
www.lavryengineering.com
Click on support, and it is the first artical under "white papers". It is
called "Sampling Theory".
It is a pdf artical and can be downloaded and printed, but the plots are in
color (and I do refer to the colors), so color printer is better.
Or, if you rather not stay connected, you can download it and view on the
screen...

The artical is educational, but it is not just "old rehash". Some of the
material aproaches things from "different angles", though all within the
bounds of science and engineering.

best regards to all

Dan Lavry

A very good article Dan. I especially liked the derivation of the sinc
function as the sum of an infinite number of cosine waves. Thank you.

"dan lavry" wrote in message
om...
Around the end of 2003, on a thread called 384KHz (regarding fast
sampling),
I promised to post an artical on sampling with some focus regarding the
ridiculess 384KHz and 192KHz trend.
It took some work, and it is a long paper. If interested, go to
www.lavryengineering.com
Click on support, and it is the first artical under "white papers". It is
called "Sampling Theory".
It is a pdf artical and can be downloaded and printed, but the plots are
in
color (and I do refer to the colors), so color printer is better.
Or, if you rather not stay connected, you can download it and view on the
screen...

The artical is educational, but it is not just "old rehash". Some of the
material aproaches things from "different angles", though all within the
bounds of science and engineering.

best regards to all

Dan Lavry



Thanks Dan!

Is there science out there that supports human hearing past 20K? ...Sounds
like you believe that to be the case?
-Willow


"Willow" wrote in message
s.com...
Dan,
Sounds like you're rapping up a topic here....but I would like to
know -exactly- your opinion as a designer about the implementation of
clock
speeds past the nyquist rate. Specifically, since nyquist stands intact,
what are the benefits to any rate past this mark? If something does seem
to
produce a better image of the original (image at lower clock that is at or
above nyquist) can you conlude that it is not a function of nyquist but
rather an inperfection in device physics that somehow adds/subtracts to
image quality? Aliasing etc...?

willow


"dan lavry" wrote in message
om...
S O'Neill wrote in message
...
Arny Krueger wrote:

I'd take issue with this statement, but not with your general issue.
The
people who dreamed up 192 KHz sampling did know math, engineering,
science
and technology. The problem is that they weren't driven by a desire
for
better sound quality at a reasonable price.

Well, my answer, in the spirit of the 9/11 commision investigation: I
do not recall what I said and have to look back in my files :-)

Seriously, regarding Arny's comments: what I meant to say is that
those that argue that 192KHz is good do not know math, engineering,
science and technology. I thought I was clear about the fact that many
of the implementers are simply afraid to rock the boat, be tagged as a
"non team player", limit their career advancment potential or simply
be fired. I agree that these implementers know math. I guess I was not
clear enough.

As a guy who's been an engineering VP and had to deal with the Sales
and
Marketing VP, I can assure you that engineers do not even HAVE brain
children (and only have "brains" when someone wants something), and the
S&M
VP has all the ideas and does all the real work so Mr. Lavry's statement
is
absolutely correct. An engineer's main purpose is to use math,
engineering,
science, and technology to extend the schedule beyond next week.

I am glad to hear you say it. I tend to agree that most engineers have
their nose pointed at a device or a CRT, and they do not look at what
happens around them. So the responsibility for the 192KHz crock is on
those that run the companies. I am not sugesting that the CEO's,
marketing VP's and managment let the engineers decide what to make or
market. I am sugesting that the system is broken, when managment
decides to go forward without the technical input from the engineers.
Or worst yet, they have the input and know it is a crock and proceed
with it. I am not going to say which of the 2 it is. I guess it is
safer and nicer to think of it is a "broken system".

Again, in the spirit of the 9/11 commision investigation: History will
(at best) view that redicules temporary trend to 192KHz audio sampling
as insufficient material forward to the decision makers :-)

Someone should point out to those folks that Moor's law does not apply
to the ear. The ear bandwidth does not double every few years :-)

And my dog does not hear 192KHz sampling either...

BR
Dan Lavry

Willow wrote:
Is there science out there that supports human hearing past 20K? ...Sounds
like you believe that to be the case?

You can make a good argument that, even though pure tones over 20KC are
not audible, that the added bandwidth makes transients more accurate.
That is, though you might not be able to hear a 21 KC note, having the
21 KC components on a 7 KC note may make an audible effect.

I have not seen a good well-conducted study show that this is the case,
but I haven't seen anything definitive saying that it's not the case either.

What Dan is pointing out is that the only thing the higher sample rates buy
you is ultrasonic response, and sometimes they buy you ultrasonic response
only at the penalty of degraded linearity. So if the ultrasonic stuff is
NOT audible, then there is therefore no reason to use the higher rates.
--scott

--
"C'est un Nagra. C'est suisse, et tres, tres precis."

I can hear bats.
One I recorded this week does not appear to have any sound below 25k.
I can hear it on the recording and I can hear it live.
When down sampled 5x it sounds pretty pure to me.

24/96 uses disc space so sorry for the 3.7meg download if you want to listen
and comment.
http://home.comcast.net/~richpeet/bat.wav

So do you think I can hear above 21,000?
Rich Peet

Scott Dorsey wrote in message
...
Willow wrote:
Is there science out there that supports human hearing past 20K?
....Sounds
like you believe that to be the case?

You can make a good argument that, even though pure tones over 20KC are
not audible, that the added bandwidth makes transients more accurate.
That is, though you might not be able to hear a 21 KC note, having the
21 KC components on a 7 KC note may make an audible effect.

I have not seen a good well-conducted study show that this is the case,
but I haven't seen anything definitive saying that it's not the case
either.

What Dan is pointing out is that the only thing the higher sample rates
buy
you is ultrasonic response, and sometimes they buy you ultrasonic response
only at the penalty of degraded linearity. So if the ultrasonic stuff is
NOT audible, then there is therefore no reason to use the higher rates.
--scott

--
"C'est un Nagra. C'est suisse, et tres, tres precis."

Rich Peet wrote:

I can hear bats.

So can I, and most other people.

One I recorded this week does not appear to have any sound below 25k.

Say what?

I can hear it on the recording and I can hear it live.

That has to do with all the content 16 KHz.

When down sampled 5x it sounds pretty pure to me.

Say what?

24/96 uses disc space so sorry for the 3.7meg download if you want to
listen and comment.
http://home.comcast.net/~richpeet/bat.wav

So do you think I can hear above 21,000?

This recording has a ton of content 16 KHz. Have you analysed it with a
FFT?

If I downsample it to 44/16 it only loses about 2 dB of average level.

It must be some sort of harmonic I hear because if I do a FFT filter of all
freqs below 20,000 then I hear nothing.

Rich

Rich Peet wrote in message
news:9xWnc.8347$UQ.462043@attbi_s51...
I can hear bats.
One I recorded this week does not appear to have any sound below 25k.
I can hear it on the recording and I can hear it live.
When down sampled 5x it sounds pretty pure to me.

24/96 uses disc space so sorry for the 3.7meg download if you want to
listen
and comment.
http://home.comcast.net/~richpeet/bat.wav

So do you think I can hear above 21,000?
Rich Peet

Scott Dorsey wrote in message
...
Willow wrote:
Is there science out there that supports human hearing past 20K?
...Sounds
like you believe that to be the case?

You can make a good argument that, even though pure tones over 20KC are
not audible, that the added bandwidth makes transients more accurate.
That is, though you might not be able to hear a 21 KC note, having the
21 KC components on a 7 KC note may make an audible effect.

I have not seen a good well-conducted study show that this is the case,
but I haven't seen anything definitive saying that it's not the case
either.

What Dan is pointing out is that the only thing the higher sample rates
buy
you is ultrasonic response, and sometimes they buy you ultrasonic
response
only at the penalty of degraded linearity. So if the ultrasonic stuff
is
NOT audible, then there is therefore no reason to use the higher rates.
--scott

--
"C'est un Nagra. C'est suisse, et tres, tres precis."

On 10 May 2004 17:31:02 -0400, (Scott Dorsey) wrote:

You can make a good argument that, even though pure tones over 20KC are
not audible, that the added bandwidth makes transients more accurate.
That is, though you might not be able to hear a 21 KC note, having the
21 KC components on a 7 KC note may make an audible effect.

The same general argument might apply for recordings intended for
further processing, like noise removal, or for transcriptions from
antique media.

It may be easier for processing algorythmi (!) to do their thing
with the most complete accounting of the original materials. For
durned sure trying to ignore the frequently large ultrasonics of the
nasty analog world causes grief in that world.

Chris Hornbeck

Scott Dorsey wrote:

Willow wrote:

Is there science out there that supports human hearing past 20K? ...Sounds
like you believe that to be the case?


You can make a good argument that, even though pure tones over 20KC are
not audible, that the added bandwidth makes transients more accurate.
That is, though you might not be able to hear a 21 KC note, having the
21 KC components on a 7 KC note may make an audible effect.

You can also make the argument that the basilar membrane is
not a resonant structure and does not use resonant elements
that use sinusoids as a decomposition basis but rather
decomposes sound neurally in which case all bets are off
relative to sinusoidal testing having anything at all to do
with what we hear.

How that thing works that we hear with is still mostly a
mystery despite what has been published.

Check out the current thread titled "Basilar membrane
mathematics of place theory" in alt.sci.physics.acoustics
for a discussion that seems to blow away the myth of
understanding that we presume.


Bob
--

"Things should be described as simply as possible, but no
simpler."

A. Einstein

Chris Hornbeck wrote:
On 10 May 2004 17:31:02 -0400, (Scott Dorsey) wrote:

You can make a good argument that, even though pure tones over 20KC are
not audible, that the added bandwidth makes transients more accurate.
That is, though you might not be able to hear a 21 KC note, having the
21 KC components on a 7 KC note may make an audible effect.

The same general argument might apply for recordings intended for
further processing, like noise removal, or for transcriptions from
antique media.

That argument absolutely applies, and in 1990 I was using that argument
here to explain why doing click and pop removal in the analogue domain
was still more effective than doing it digitally. Finding the click is
much easier if you have substantial ultrasonic content because you're
basically looking at the second derivative of the signal.

It may be easier for processing algorythmi (!) to do their thing
with the most complete accounting of the original materials. For
durned sure trying to ignore the frequently large ultrasonics of the
nasty analog world causes grief in that world.

Absolutely.
--scott
--
"C'est un Nagra. C'est suisse, et tres, tres precis."

Scott,

You can make a good argument that, even though pure tones over 20KC are
not audible, that the added bandwidth makes transients more accurate.

I don't think a good argument can be made for that at all. Unless Fourier
was wrong (hint: he wasn't) all music and sound is comprised of discrete
sine waves of varying frequency and amplitude. So for a transient with a
fast rise time, the "fast" components are merely portions of sine waves
whose frequencies are beyond our hearing range.

Some people may be able to hear a bit past 20 KHz, but *nobody* can hear
anything even close to 48 KHz which is the basis for using a 96 KHz sample
rate.

--Ethan

thanks for the reply,


Is there science out there that supports human hearing past 20K?
....Sounds
like you believe that to be the case?

You can make a good argument that, even though pure tones over 20KC are
not audible, that the added bandwidth makes transients more accurate.
That is, though you might not be able to hear a 21 KC note, having the
21 KC components on a 7 KC note may make an audible effect.

I have not seen a good well-conducted study show that this is the case,
but I haven't seen anything definitive saying that it's not the case
either.


Yeah, i have hear that theory before. It is actually easy to test for with a
few recorded transients @ 48 and up-sample to 96. Then record same transiets
at 96, Blind test those results....Anyone game?


What Dan is pointing out is that the only thing the higher sample rates
buy
you is ultrasonic response, and sometimes they buy you ultrasonic response
only at the penalty of degraded linearity. So if the ultrasonic stuff is
NOT audible, then there is therefore no reason to use the higher rates.

Actually there are more trade off than those mentioned. Doesn't Dan build a
box that sample up to 96 and why not 192 or 384 etc....? I have not read the
white paper yet, I would assume he answers these q's there.

Regards
Willow

Willow wrote:
Is there science out there that supports human hearing past 20K?
...Sounds
like you believe that to be the case?

You can make a good argument that, even though pure tones over 20KC are
not audible, that the added bandwidth makes transients more accurate.
That is, though you might not be able to hear a 21 KC note, having the
21 KC components on a 7 KC note may make an audible effect.

I have not seen a good well-conducted study show that this is the case,
but I haven't seen anything definitive saying that it's not the case
either.

Yeah, i have hear that theory before. It is actually easy to test for with a
few recorded transients @ 48 and up-sample to 96. Then record same transiets
at 96, Blind test those results....Anyone game?

How do you know you aren't testing some difference between the way the
A/D converter works at the two different rates? Or some artifact of
the SRC? The problem is that there are so many of these compounding
variables involved.

What Dan is pointing out is that the only thing the higher sample rates
buy
you is ultrasonic response, and sometimes they buy you ultrasonic response
only at the penalty of degraded linearity. So if the ultrasonic stuff is
NOT audible, then there is therefore no reason to use the higher rates.

Actually there are more trade off than those mentioned. Doesn't Dan build a
box that sample up to 96 and why not 192 or 384 etc....? I have not read the
white paper yet, I would assume he answers these q's there.

Yes.
--scott
--
"C'est un Nagra. C'est suisse, et tres, tres precis."

Willow wrote:
thanks for the reply,


Is there science out there that supports human hearing past 20K?
...Sounds
like you believe that to be the case?

You can make a good argument that, even though pure tones over 20KC
are not audible, that the added bandwidth makes transients more
accurate. That is, though you might not be able to hear a 21 KC
note, having the 21 KC components on a 7 KC note may make an audible
effect.

Change the waveform, then for sure you change the spectral content. Above
500-1000 KHz, the ear is very spectral-centric.

I have not seen a good well-conducted study show that this is the
case, but I haven't seen anything definitive saying that it's not
the case either.

The proof is in the filtering:

http://www.pcabx.com/technical/low_pass/index.htm

Yeah, i have hear that theory before. It is actually easy to test for
with a few recorded transients @ 48 and up-sample to 96. Then record
same transients at 96, Blind test those results....Anyone game?

Been there done that, except at a variety of sample rates:

http://www.pcabx.com/technical/sample_rates/index.htm

What Dan is pointing out is that the only thing the higher sample
rates buy
you is ultrasonic response, and sometimes they buy you ultrasonic
response only at the penalty of degraded linearity. So if the
ultrasonic stuff is NOT audible, then there is therefore no reason
to use the higher rates.

With ultrasonic response comes lots of ultrasonic noises. For example the
recording of a Bat I just downloaded lately had an interesting
agglomeration of noise above 30 KHz that didn't seem to vary with the bat.

Actually there are more trade off than those mentioned. Doesn't Dan
build a box that sample up to 96 and why not 192 or 384 etc....?

All you need is Audition, it resamples up to 100 MHz. Seems like high that
would be high enough... LynxTWO series audio interfaces among others,
perform well at up 192 KHz sampling.

I have not read the white paper yet, I would assume he answers these
q's there.

Listen for yourself!

Scott Dorsey wrote:
Willow wrote:
Is there science out there that supports human hearing past 20K?
...Sounds
like you believe that to be the case?

You can make a good argument that, even though pure tones over 20KC
are not audible, that the added bandwidth makes transients more
accurate. That is, though you might not be able to hear a 21 KC
note, having the 21 KC components on a 7 KC note may make an
audible effect.

I have not seen a good well-conducted study show that this is the
case, but I haven't seen anything definitive saying that it's not
the case either.

Yeah, i have hear that theory before. It is actually easy to test
for with a few recorded transients @ 48 and up-sample to 96. Then
record same transients at 96, Blind test those results....Anyone
game?

How do you know you aren't testing some difference between the way the
A/D converter works at the two different rates?

Point taken. The route I took at www.pcabx.com was to record at 96 KHz, and
then downsample to the test sample rate and then upsample back to 96 KHz.

Or some artifact of the SRC?

Run technical tests on the SRC.

The problem is that there are so many of these compounding
variables involved.

Got more?

If the listening tests come out "no differences" then the alleged
confounding influences must not be all that significant. Or, somehow they
managed to exactly cancel out the effect of the difference in sample rates.
Seems pretty darn unlikely!

Ethan Winer wrote:

Scott,


You can make a good argument that, even though pure tones over 20KC are

not audible, that the added bandwidth makes transients more accurate.

I don't think a good argument can be made for that at all. Unless Fourier
was wrong (hint: he wasn't) all music and sound is comprised of discrete
sine waves of varying frequency and amplitude.

A time domain signal is what it is, no more and no less. If
you have a very particular kind of hardware that can perform
correlations of it with complex exponentials then you can
get as an output a domain transformation in terms of complex
frequency that was first noticed by Fourier and can be
useful for computation. There is no evidence whatsoever
that the ear/brain performs that kind of transformation and
it is so unlikely compared to more useful ones in the
evolutionary sense that it should be entirely discarded as a
possibility.

OTOH, there are decomposition basis classes that seem more
likely which would have relatively small responses to
sinusoidal stimuli, if any in certain ranges. The fact that
the ear/brain fails to respond to sinusoidal stimuli in a
frequency range says almost nothing about how it will
respond to acoustic stimuli which, if analysed in the
Fourier sense, would show harmonic content there.

Discussions of what we can or can't hear that are argued on
the basis of Hz are in fact baseless in a very literal sense.

That's not to say that experimental work such as Arny has
done with determining what lowpass corner renders real
acoustic data perceptually different isn't extremely
valuable because, of course, physics says that there will be
some upper corner above which the physical mechanism cannot
respond in any way but let's just forget about how it might
respond below that limit and how that relates to sinusoidal
hearing tests.


Bob
--

"Things should be described as simply as possible, but no
simpler."

A. Einstein

The most important fact we have is the most obvious one; sound is pressure
variations, and our hearing mechanism, starting from the pressure variations
arriving at the eardrum, is not brickwall-filtered. We feel 0.5 Hz, and our
brain reacts to 70kHz. Even if it's subconcious and we claim "we can't hear
it", the energy doesn't mystically disappear. These kind of frequencies
affect the naturalness of the sound, but their importance is another
matter...
Personally, I'm happy working without the ultrasonic range. The whole
ultrasonic range brings too many problems compared to its benefits. That is,
in audio reproduction.

Bob and Tommi,

I think you're both making this more complicated than necessary. A fast rise
time is just that, and if there are 70 KHz components we don't hear them. I
can't imagine how we could sense them either since they'd have to get
through our ears to reach our brains. The ear and brain don't "transform"
anything. They simply respond to frequencies that aren't so high the
mechanical parts can't vibrate.

As you acknowledge, low-pass filter tests are absolutely valid, and my own
tests many years ago convinced me that this is all one huge non-issue. If
disk space and CPU power were free, then sure, record at a 20 MHz sample
rate for all I care. But for now, anyway, these resources are not free, and
that's the real issue in practical terms.

--Ethan

Tommi wrote:
The most important fact we have is the most obvious one; sound is
pressure variations, and our hearing mechanism, starting from the
pressure variations arriving at the eardrum, is not
brickwall-filtered. We feel 0.5 Hz, and our brain reacts to 70kHz.

The half hertz I get, but the 70 KHz escapes me. Please explain.

Even if it's subconscious and we claim "we can't hear it", the energy
doesn't mystically disappear.

There's nothing mystical at all about how it disappears. But, that doesn't
mean that anybody hears it.

These kind of frequencies affect the
naturalness of the sound, but their importance is another matter...

That would be an unproven assertion, even an assertion that escapes proof
when diligently pursued.

Personally, I'm happy working without the ultrasonic range.

So is anybody who is interested in that which is heard, as opposed to that
which is supposed.

The whole ultrasonic range brings too many problems compared to its
benefits.

Open the windows wider, and more dirt comes in.

That is, in audio reproduction.

The ear is not perfectly linear. Ultrasonic components _could_ intermodulate to
produce audible components. (There's a speaker system based on this principle.)

Whether or not this actually occurs with ordinary musical sounds is something I
don't know.

I don't mean to steal a thread here but as I was testing a higher sample
rate to begin with:

If you are talking about the bat from this thread I noticed the noise too.
The mic was pointed toward an expressway about 1/2 mile out so I suspect
that as the source.

Would you agree that the noise appears to be environmental?

The reason that is important to me is that then I can use that noise to
determine if my mic is responding fairly well from 1 to 40,000 cycles with a
few lower frequency bands of trouble. Testing the system was the original
goal here.
The loud noise is a stone I tossed up to attract the bat (works every time)
which then bounced off the roof.

recording chain was: Senn mkh-110 (unbalanced),homemade mic power supply,
rme quadmic pre, rme multiface, Audition 1.0, toshiba laptop with xp.

Rich Peet

Arny Krueger wrote in message
...
....
With ultrasonic response comes lots of ultrasonic noises. For example the
recording of a Bat I just downloaded lately had an interesting
agglomeration of noise above 30 KHz that didn't seem to vary with the
bat.

Actually there are more trade off than those mentioned. Doesn't Dan
build a box that sample up to 96 and why not 192 or 384 etc....?

All you need is Audition, it resamples up to 100 MHz. Seems like high
that
would be high enough... LynxTWO series audio interfaces among others,
perform well at up 192 KHz sampling.

I have not read the white paper yet, I would assume he answers these
q's there.

Listen for yourself!

William Sommerwerck wrote:

The ear is not perfectly linear. Ultrasonic components _could_ intermodulate to
produce audible components. (There's a speaker system based on this principle.)
...snip..

I think I've missed something. Are you saying the ultrasonic speaker system uses
the ear's
non linearity, or are these just two (somewhat) isolated facts?

I believe the speaker system you are talking about produces sound emanating from
remote
locations in space through nonlinear interactions of ultrasonic beams with air. I
don't believe
ear linearity has anything to do with that system.

Buy the way, the physics that allow that "speaker system" to work also relate to
the acoustic
refrigerator... :-)
[ Vortex cooling is another story. ]

Later...

Ron Capik
--

William Sommerwerck wrote:

The ear is not perfectly linear.

Right, nonlinearity sets in pretty strongly above 75-85 dB. the effect is
strong enough that audible differences in DBTs can "go away" if the volume
is too high.

Rich Peet wrote:
I don't mean to steal a thread here but as I was testing a higher
sample rate to begin with:

If you are talking about the bat from this thread I noticed the noise
too. The mic was pointed toward an expressway about 1/2 mile out so I
suspect that as the source.

Would you agree that the noise appears to be environmental?

Let me put it this way, the shape of the lump is all wrong for the usual
switchmode power supply noise, etc.

The reason that is important to me is that then I can use that noise
to determine if my mic is responding fairly well from 1 to 40,000
cycles with a few lower frequency bands of trouble. Testing the
system was the original goal here.
The loud noise is a stone I tossed up to attract the bat (works every
time) which then bounced off the roof.

OK, that explains some things.

recording chain was: Senn mkh-110 (unbalanced),homemade mic power
supply, rme quadmic pre, rme multiface, Audition 1.0, toshiba laptop
with xp.

You might want to look at my related stuff posted at:

http://64.41.69.21/technical/sample_rates/index.htm

Lots of spectrograms, spectral analyses, and downloadable samples @24/96.
Equipment list is there, too.

"Arny Krueger" wrote in message
...
Tommi wrote:
The most important fact we have is the most obvious one; sound is
pressure variations, and our hearing mechanism, starting from the
pressure variations arriving at the eardrum, is not
brickwall-filtered. We feel 0.5 Hz, and our brain reacts to 70kHz.

The half hertz I get, but the 70 KHz escapes me. Please explain.

I bet most of you guys have read already read this, but:

http://www.sowter.co.uk/pdf/ultrasonichearing.pdf

These kind of frequencies affect the
naturalness of the sound, but their importance is another matter...

That would be an unproven assertion, even an assertion that escapes proof
when diligently pursued.

Most cymbals have over 40% of their energy in the 20kHz+ range.

Tommi wrote:
"Arny Krueger" wrote in message
...
Tommi wrote:
The most important fact we have is the most obvious one; sound is
pressure variations, and our hearing mechanism, starting from the
pressure variations arriving at the eardrum, is not
brickwall-filtered. We feel 0.5 Hz, and our brain reacts to 70kHz.

The half hertz I get, but the 70 KHz escapes me. Please explain.

I bet most of you guys have read already read this, but:

http://www.sowter.co.uk/pdf/ultrasonichearing.pdf

Yes, been there, deconstructed it.

These kind of frequencies affect the
naturalness of the sound, but their importance is another matter...

That would be an unproven assertion, even an assertion that escapes
proof when diligently pursued.

Most cymbals have over 40% of their energy in the 20kHz+ range.

I'm not sure of that. I've seen a lot of 24/96 cymbals recordings with
energy peaking in the low teens. The word cymbals covers a lot of territory.

Take a look at http://www.pcabx.com/technical/sample_rates/index.htm

The keys recording has a similar amount of energy between 22 and 48 KHz. But
when you do the DBT listening tests...

In article ,
"Tommi" wrote:

"Arny Krueger" wrote in message
...
Tommi wrote:
The most important fact we have is the most obvious one; sound is
pressure variations, and our hearing mechanism, starting from the
pressure variations arriving at the eardrum, is not
brickwall-filtered. We feel 0.5 Hz, and our brain reacts to 70kHz.

The half hertz I get, but the 70 KHz escapes me. Please explain.

I bet most of you guys have read already read this, but:

http://www.sowter.co.uk/pdf/ultrasonichearing.pdf

Yes, but alpha wave production is a rather crude way of establishing what is
going on here. Just closing your eyes can increase alpha production by 50% or
more. It is evident that something is being picked up by the brain but there's
no physiological explanation for the effect observed. If I saw auditory nerve
firing in response to ultrasonic input I'd consider it hearing. This is
probably, as the authors mention, a modulation effect, but it may well be
important in perception.


These kind of frequencies affect the
naturalness of the sound, but their importance is another matter...

That would be an unproven assertion, even an assertion that escapes proof
when diligently pursued.

Most cymbals have over 40% of their energy in the 20kHz+ range.


Virtually every instrument we've tried has some energy above 20 kHz.

-Jay
--
x------- Jay Kadis ------- x---- Jay's Attic Studio ------x
x Lecturer, Audio Engineer x Dexter Records x
x CCRMA, Stanford University x http://www.offbeats.com/ x
x-------- http://ccrma-www.stanford.edu/~jay/ ----------x

William,

The ear is not perfectly linear.

I'm fully aware of this, and to me it's a completely different issue.

I sometimes play percussion in a local symphony, and that includes orchestra
bells. When playing two notes very loudly I can easily hear the IM products
that are generated inside my ears. How close musically the notes are to each
other determines which low frequency beat note I hear. I agree that some of
the beating is between ultrasonic components. But this does not mean an
audio system needs to capture ultrasonics! Moreover, this IM effect is not
audible out in the audience, and even I hear it only when playing very
loudly.

To take this to the logical conclusion, the "ultrasonics matter" camp would
have us capture everything up to 48 or 96 KHz or even higher, and they'd
have us buy loudspeakers that can reproduce that high, merely so we can play
it really loud while standing next to the speakers so our ears can generate
IM distortion.

No thanks.

--Ethan