What is the advantage on high-sampling rate ?

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

"Arthur" <arthurc99@yahoo.com> writes:

> 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..

To line the pocketbooks of media and manufacturing moguls with
greenery.
-- 
Randy Yates
Sony Ericsson Mobile Communications
Research Triangle Park, NC, USA
randy.yates@sonyericsson.com, 919-472-1124

Arthur wrote:
> 
> 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..

Analogue audio amplifers typically have a flat frequency response to 100kHz
or higher. Tweeters on mid to high price range loudspeakers are also capable
of reproducing frequencies well above 20kHz.

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.

Erik
-- 
+-----------------------------------------------------------+
  Erik de Castro Lopo  nospam@mega-nerd.com (Yes it's valid)
+-----------------------------------------------------------+
"The X-files is too optimistic. The truth is not out there."
-- Anthony Ord

Hi Arthur,

I think you're confusing things - everything BELOW 20 Hz will most
likely be cut off. At least, this is generally done.

The upper frequency limit depends on the playback gear - the 22kHz
upper limit comes from the typical sampling rate being 44.1kHz. If the
sample rate is higher, so is this limit.

It still stands to reason whether the higher sampling rates make any
sense perceptually. Personally, I'm not really convinced that they do,
but why not letting people decide on their own...

--smb



"Arthur" <arthurc99@yahoo.com> wrote:
> 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

Hi My Friend,

I don't want to get into the debate like "let people decide"...
I believe that this is a Signal Processing newsgroup..  So, I would like to
discuss about the Tech. or Theoretical things only.  From my definition
(maybe from many textbooks).  I found the following :
- Audible sound (20 Hz - 20 KHz)
- Bat normal Ultrasound range (10 KHz - 60 KHz)
- Dolphin normal Ultrasound range (7 KHz - 15 KHz) Burst (20 KHz - 170 KHz)

If some comments are correct, my speaker system may well attract many BATS
or DOLPHINS to come into my house.  Please, I really don't want to listen
the BAT/DOLPHIN to talk to each other.

Regards
Arthur

"Stephan M. Bernsee" <stephan.bernsee@web.de> ???
news:38ab652c.0404210523.1b296f30@posting.google.com ???...
> Hi Arthur,
>
> I think you're confusing things - everything BELOW 20 Hz will most
> likely be cut off. At least, this is generally done.
>
> The upper frequency limit depends on the playback gear - the 22kHz
> upper limit comes from the typical sampling rate being 44.1kHz. If the
> sample rate is higher, so is this limit.
>
> It still stands to reason whether the higher sampling rates make any
> sense perceptually. Personally, I'm not really convinced that they do,
> but why not letting people decide on their own...
>
> --smb
>
>
>
> "Arthur" <arthurc99@yahoo.com> wrote:
> > 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

Arthur wrote:

> 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..

There may be a mix of technical advantages with propaganda to
sell more new-and-improved equipment.

Higher sampling rate may lead to easier designs with less
distortion.  Think of the very first CD players;  some of
them were reported to have noticeable distortion at high
frequencies.  This was presumably caused by defects in the
analog filtering stage -- it was very critical, since you
had to let 20kHz through with hopefully less than 3dB
attenuation, but at 22.05kHz there should be an attenuation
of 90dB (well, ok, let's say 60, or even 30, assuming that
the best of ears could not hear that).  That's a pretty
tough filter to achieve with analog components that may
have 1% or 0.1% tolerance  (you operate the CD player at
10 degrees more than usual, and the resistors and capacitors
of the output filter varied by 0.5% and your filter went
crazy.

Sure, then oversampling came, and you "simulate" the effect
of having a high sampling rate, which simplifies the design
of the reconstruction analog filter.  But that does introduce
a little bit of distortion -- at the very least, it makes it
hard to do a *good* oversampling filter.

Many other tricks have come along, but they all -- in one
way or another -- simulate the effect of having a higher
sampling rate, such that aliasing is easier to eliminate
with simpler, stable filters.

So, how about not simulating a higher sampling rate, but
actually having a higher sampling rate?  Given that
technology now allows it, why not? (I just got a tiny
1" by 1" thing for my digital camera that holds almost
twice as much information as a CD -- and there are
microdrives with 2GB capacity!!!)

My point is that higher sampling rates do help, although
arguably they're not strictly necessary.  Then again, the
"more-bits-more-sampling-rate-is-better-comma-buy-the-new-
and-improved-super-digital-equipment" syndrome is part of
the mix.

Carlos
--

Stephan M. Bernsee wrote:

> Hi Arthur,
> 
> I think you're confusing things - everything BELOW 20 Hz will most
> likely be cut off. At least, this is generally done.
> 
> The upper frequency limit depends on the playback gear - the 22kHz
> upper limit comes from the typical sampling rate being 44.1kHz. If the
> sample rate is higher, so is this limit.
> 
> It still stands to reason whether the higher sampling rates make any
> sense perceptually. Personally, I'm not really convinced that they do,
> but why not letting people decide on their own...
> 
> --smb

Many people who decide on their own end up buying centimeter-diameter
gold-plated loudspeaker wire. Having spent an outrageous amount for the
cables, they will inevitably hear the improvement these cables make.
(Many of those same people might swear that their car's gas mileage and
acceleration is improved by after-market gear-shift knobs.)

http://www.homegrownaudio.com/speaker_hybrid.html asserts that while
silver supply wires greatly improve sound quality, it's OK if the return
wires are made of copper!?! By the way, silver is indeed a better
conductor than copper, but only by a very small fraction of a wire size.

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

"Arthur" wrote:
>
> I believe that this is a Signal Processing newsgroup..  So, I would like to
> discuss about the Tech. or Theoretical things only.  From my definition
> (maybe from many textbooks).  I found the following :
> - Audible sound (20 Hz - 20 KHz)
> - Bat normal Ultrasound range (10 KHz - 60 KHz)
> - Dolphin normal Ultrasound range (7 KHz - 15 KHz) Burst (20 KHz - 170 KHz)

Yes, that sounds reasonable. Humans can in fact perceive sounds with a
fundemantal frequency as low as 16Hz. Anything lower will be perceived
as individual pulses.

> If some comments are correct, my speaker system may well attract many BATS
> or DOLPHINS to come into my house. 

They might indeed. That's why I said it stands to reason whether such
sample rates make sense perceptually - for a human.

They can make things easier on the signal processing side of things,
since the aliasing problems will also be moved in areas that are
inaudible.

--smb

Arthur wrote:
> Hi My Friend,
> 
> I don't want to get into the debate like "let people decide"...
> I believe that this is a Signal Processing newsgroup..  So, I would like to
> discuss about the Tech. or Theoretical things only.  From my definition
> (maybe from many textbooks).  I found the following :
> - Audible sound (20 Hz - 20 KHz)

You can not completely separate both issues.  For that matter,
from the purely theoretical point of view, the only answer to
your original question is:  "whit higher sampling rate, you
get a higher limit for the maximum representable bandwidth"

Pretty useless answer if it's not associated to some context;
I mean, a bandwidth of 5kHz is good because it is higher than
4kHz?  Is a 20Hz bandwith good?  After all, it is higher than
a 10Hz bandwidth.

You have to put things in a certain context.  And the concept
of "Audible sound" (which you got wrong, BTW) is not a "purely
tech. or theoretical" thing.  The definition of "audible sound"
is related to a human perception process that we are far from
understanding in detail  (we have *some* evidence of what
happens up until the neuron receptors -- from there on, there
is *a lot* of magic going on in our brains, with an outcome
that can not even be defined from a scientific/technological
point of view:  a psychological sensation of sound, with all
the emotional implications it might have -- a familiar voice,
a pleasurable musical sound, etc.)

You could restrict the context of the discussion saying that
"if we assume and accept that no human can hear above 20kHz,
what is the advantage of higher sampling rates?" -- but still,
your point would be flawed, in that any advantage can only
be an advantage when put in the context of human perception
of sound.

All that said, maybe my other message in this thread is
closer to the kind of answer you were looking for?  Still,
do not ignore the fact that wanting to have a bandwidth of
more than 20kHz is a valid reason, even if for 99.99% of
the human population it doesn't make a difference.

Carlos
--

"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..

Apart from the issue of audible bandwidth, having more frequency "headroom" is
useful.  Digital filters tend to go a bit crazy near the Nyquist frequency, so
moving that frequency well above the accepted audible range is a good thing.  As
has been pointed out by others, frequency headroom also simplifies the analog
input/output filtering stages as well as sample rate conversion.  Remember that
the Nyquist criteria states that it is _possible_ to perfectly reconstruct the
original waveform, but not that it is _practical_ or _easy_ to do so.  Increased
frequency headroom generally makes it easier.