What's the use of a 192 kHz sample rate?

On May 3, 8:29 am, Randy Yates <ya...@ieee.org> wrote:
> rickman <gnu...@gmail.com> writes:
> > [...]
> > When I press the keys on the right, I
> > hear more of a click than a ping (maybe it's the piano)!
>
> Then you can no longer hear up to 4186 Hz.
>
>  http://en.wikipedia.org/wiki/Piano_key_frequencies

Like I said, it may be the piano that doesn't really produce much of a
ping on the highest notes.  But all of us have some hearing loss as we
get older.  The point is that you can't judge how others hear based on
what we can hear.


> You are free to think what you want about hearing. I choose to side with
> objective measurements verifying again and again over several decades
> the same conclusions rather than a few crackpot audiophools that claim
> they're different without any supporting objective evidence.
>
> And even if one or two actually could hear beyond 20 kHz, they're the
> Robert Wadlow's of the audio world - should we start building houses
> with 10-foot ceilings because 1 out of a billion will be over 8 feet
> tall?

I never said that *anyone* can hear sounds above 20 kHz.  I said that
there are people who can hear the difference between systems that use
higher sample rates than 48 kHz.  The real issue is about the
electronics and how they are measured *compared* to human hearing.
Distortion is the real issue.  Filters introduce distortion and some
people can hear the distortion produced by converters running at 48
kHz.

I suppose it is possible that my friend was mislead (and therefor
myself).  I have no first hand knowledge of the sound tests.  But he
is not a person to believe in rubbish.  In fact, he is a person who is
very intellectually critical.  This is one of the few times he could
not dismiss claims that run counter to the science.

Oh, about the Robert Wadlow's of the acoustic world... if lumber in 10
foot lengths were the same price as 8 foot lengths, why *not* build
homes with 10 foot ceilings?  At one time 9 foot ceilings were the
norm.  What is the delta in price, power or anything else going from
48 kHz to 196 kHz sample rates???  My present design is using a CODEC
capable of 192 kHz sample rate even though I am running it at 8 kHz.
It is actually a bit cheaper than a similar chip from the same maker
that only runs at 96 kHz.  The power consumption is only a few mW
higher and I have no idea of what the OP meant by the waste of
"time"...

Rick

rickman wrote:


>>Utter nonsense - unless of course you can cite some proper tests.
> 
> And what do you base this statement on?

The ultimate reason for the audio systems is making the people happy. If 
someone is happy because of 192kHz sample rate, and willing to pay for 
that, then why do you need to proove anything? Heck, if someone orders a 
192MHz audio system, it would be my pleasure to do this project.


Vladimir Vassilevsky
DSP and Mixed Signal Design Consultant
http://www.abvolt.com

Vladimir Vassilevsky wrote:
> 
> 
> rickman wrote:
> 
> 
>>> Utter nonsense - unless of course you can cite some proper tests.
>>
>> And what do you base this statement on?
> 
> The ultimate reason for the audio systems is making the people happy. If 
> someone is happy because of 192kHz sample rate, and willing to pay for 
> that, then why do you need to proove anything? Heck, if someone orders a 
> 192MHz audio system, it would be my pleasure to do this project.

Quite right, too. If engineers only built what people actually need, you 
and I would probably be looking for another occupation.

Steve

I'm not sure your citations actually prove what you claim they do.

On May 3, 10:19 am, "Ethan Winer" <ethanw at ethanwiner dot com>
wrote:
> Randy,
>
> > Greed. They think that the general public is dumb enough to buy into the
> > lie that they really need such a system and would then spend lots of money
> > repurchasing what they already have.
>
> LOL, you nailed it man. Same with music, where they hope you'll buy all the
> same titles again to play on your new unnecessary hardware.
>
> Besides the obvious waste, as Radium pointed out, this nonsense has been
> discredited fully:
>
> Audio Critic summary of the AES hi-res fallacy article:http://theaudiocritic.com/blog/index.php?op=ViewArticle&articleId=41&...

This seems to indicate that the tests do show the higher formats to be
equivalent to CDs.  I assume that when they refer to a "16-bit/44.1-
kHz A/D/A processor" they mean the are digitizing and then restoring
to analog a signal from a higher end system.  Assuming that the tests
were done correctly, and I have no reason to believe they weren't,
this seems pretty convincing.


> More from the authors themselves:http://www.bostonaudiosociety.org/explanation.htm

Maybe I just don't understand this report, but I see sections where
they claim that the blind tests showed 100% correct results??!!!
Doesn't that indicate that the listener *could* tell the difference?
Unfortunately the writeup is very lengthy in the description of the
systems and very, very terse in the description of what they are
actually measuring...  Correct me if I am misinterpreting their
results.


> Paul Lehrman commenting in Mix magazine:http://mixonline.com/recording/mixing/audio_emperors_new_sampling/ind...

This is less clear.  He is just commenting on the tests cited in the
first article.  The actual test report costs $20 from AES.


> Nobody can hear, or perceive, or be influenced by ultrasonic content, even
> if they think they can. Here's my best explanation for why people sometimes
> report hearing differences even when none can possibly exist:

The question is *not* about ultrasonic content.  The question is about
recording and playback systems using different sample rates.


> http://www.ethanwiner.com/believe.html
>
> > And even if one or two actually could hear beyond 20 kHz, they're the
> > Robert Wadlow's of the audio world - should we start building houses with
> > 10-foot ceilings because 1 out of a billion will be over 8 feet tall?
>
> More to the point, even if a few people really can just barely detect when
> frequencies above 20 KHz are removed, who cares? Just because someone can
> perceive 21 KHz doesn't mean that music they hear must contain those
> frequencies to be satisfying.

You are free to buy any system you want.  Why do you care what other
people use?

On May 3, 4:16 am, Randy Yates <ya...@ieee.org> wrote:
> "Green Xenon [Radium]" <gluceg...@excite.com> writes:
>
> > [...]
> > On average, what is the minimum sample rate for a guy in his early to
> > mid 20s who likes treble?
>
> The curve on p.20 of
>
>  http://www.dohc.ie/publications/pdf/hearing.pdf?direct=1
>
> indicates that, even for young adults, sound at <20 kHz is
> inaudible. Based on this, a 44.1 kHz sample rate should be ample.

I think I am spending too much time on this, but your conclusion does
not follow from the data.  It's that simple.  The issue is whether the
lower sample rates work as well as higher sample rates in recording
and playback systems.  Your cursory analysis of human hearing
frequency response does not indicate anything in that regard.

On Sat, 03 May 2008 09:26:32 -0400, Greg Berchin
<gberchin@comicast.net> wrote:

>2) There's some evidence that humans' ability to hear high frequency
>transient signals exceeds their ability to hear high frequency steady
>state signals.  

I forgot to mention:  This can probably be fully explained by the fact
that transient signals have a nonzero bandwidth associated with them.
If that bandwidth extends down into the audible range, then, of
course, the signal becomes audible.  From that standpoint,
filtering-out the portion of the transient that is above the audible
range should not affect the audibility of what is left.  Still, from a
waveform fidelity point of view it might be beneficial to keep more of
it.

Greg

On Sat, 3 May 2008 07:34:24 -0700 (PDT), rickman <gnuarm@gmail.com>
wrote:

>On May 3, 8:22 am, nos...@nospam.com (Don Pearce) wrote:
>> On Sat, 3 May 2008 05:11:53 -0700 (PDT), rickman <gnu...@gmail.com>
>> wrote:
>>
>> >On May 3, 3:28 am, Randy Yates <ya...@ieee.org> wrote:
>> >> rickman <gnu...@gmail.com> writes:
>> >> > If it really is a waste of time and money to use 192 kHz ADC and DAC,
>> >> > why do you think they would do it?
>>
>> >> Greed. They think that the general public is dumb enough to buy into
>> >> the lie that they really need such a system and would then spend lots of
>> >> money repurchasing what they already have.
>>
>> >I'm curious, how do you know what unnamed people are thinking?  My
>> >understanding is that regardless of what frequencies acoustic testing
>> >says that people can hear, audiophiles can hear the difference between
>> >many of these "wasteful" features and otherwise adequate audio
>> >systems.
>>
>> Utter nonsense - unless of course you can cite some proper tests.
>
>And what do you base this statement on?  I don't have any "proper"
>studies.  I am referring to a conversation with a friend who worked in
>the field.  He couldn't hear the difference, but his customers could.
>If they came out with a product that used a "lesser" technique,
>without *knowing* what technology was behind it they would reject the
>system as not being good enough.  If they didn't know anything about
>the methods, they only had their ears to judge the equipment.  Since
>they are paying serious bucks (>$100,000 some 20 years ago) for these
>systems, they have *NO* reason to buy racks of gear that is any better
>than a lower price system.  BTW, this was professional equipment, not
>the home stuff with oxygen free speaker wires and such.
>
>You can poo-poo this sort of evaluation.  But that doesn't make you
>right.  Do you have any "proof" that no one can hear the difference?
>Do you even know what the differences are that I was talking about?
>
That is a truly idiot comment. To prove that nobody could hear it I
would have to test everybody in the world for the rest of time with
every possible type of music - and even then there is no guarantee
that the next thing I tried wouldn't be the one that revealed the
difference. All you need to do is produce one person who can reliably
hear the difference with their choice of material and the job is done.

And no, anecdote won't do. This business is full of bullshit anecdotes
- mostly involving wives hearing the difference from the kitchen even
when they didn't know what had been done.

>
>> >I have known people who worked on professional equipment.  The
>> >extremes that they have design in are all audible to the buyers of
>> >such systems.  In the audio sections of the equipment they use 15 volt
>> >rails or even higher, just to increase the SNR when the noise floor
>> >can't be lowered anymore.  They totally eliminate all digital clocks
>> >from any circuit near the audio section to prevent noise injection.
>> >From what I have seen, they use more extreme measures in high end
>> >audio than is used in sensitive military radio gear which is trying to
>> >get over 140 dB of SNR!
>>
>> More nonsense. I have worked on many radio systems, both military and
>> civil, and a typical target SNR for these radios is in the region of 6
>> to 10dB.
>
>My bad, I used the wrong term, it should have been 140 dB signal
>strength.  Yes, I need to indicate what the reference is, but I don't
>recall if it was dBmW or dBW, a 30 dB difference.
>

So a meaningless number then?

>
>> >I am not going to try to tell someone else what they can and can't
>> >hear.  I know that my hearing has dropped of dramatically to where I
>> >can no longer hear the 15 kHz emitted by TVs and I'm not sure I can
>> >hear the high notes on a piano.  When I press the keys on the right, I
>> >hear more of a click than a ping (maybe it's the piano)!  But that
>> >doesn't mean that there aren't others who can hear the distortion
>> >created by the anti-alias filters used when the ADC and DAC run at
>> >44.1 kHz.
>>
>> Doesn't mean they can either. That isn't a piece of logic that
>> commutes.
>
>I didn't say it proves that others can.  What logic are you talking
>about?  I am simply saying that you shouldn't judge what others can
>perceive by what you can or even what the general public can according
>to "proper tests".
>

It isn't a question of "others" - one is all it takes, and I can
assure you that nobody has produced him yet.

>I'm not trying to "prove" anything.  I am presenting information which
>you can consider and believe or can ignore.  But you can't say my
>statements are false unless you have some information to "prove" they
>are.  Human hearing is not a microphone connected to an amplifier.  It
>is a very complex process which even includes the brain and we
>certainly don't understand it completely.

No, it isn't information - it is urban myth and anecdote.

d
-- 
Pearce Consulting
http://www.pearce.uk.com

On May 3, 12:14 pm, nos...@nospam.com (Don Pearce) wrote:

I thought we were having a conversation.  But I don't appreciate being
called names.  Would you speak to me this way if I were standing in
front of you?  Either way you come across as being rude.

Rick

rickman wrote:
> On May 3, 4:16 am, Randy Yates <ya...@ieee.org> wrote:
>> "Green Xenon [Radium]" <gluceg...@excite.com> writes:
>>
>>> [...]
>>> On average, what is the minimum sample rate for a guy in his early to
>>> mid 20s who likes treble?
>> The curve on p.20 of
>>
>>  http://www.dohc.ie/publications/pdf/hearing.pdf?direct=1
>>
>> indicates that, even for young adults, sound at <20 kHz is
>> inaudible. Based on this, a 44.1 kHz sample rate should be ample.
> 
> I think I am spending too much time on this, but your conclusion does
> not follow from the data.  It's that simple.  The issue is whether the
> lower sample rates work as well as higher sample rates in recording
> and playback systems.  Your cursory analysis of human hearing
> frequency response does not indicate anything in that regard.

The 22kHz scanning monitors I used to use drove me crazy right up until 
my late 30s. Then, the monitors started scanning higher, and my ears 
were getting older. I'm not clear which one caused me to be free of the 
whistling first. :-)

I think a lot of the arguments about sampling rate muddle two things up 
- which, of course, the people who stand to profit from snake oil love 
very much - the rate at which you convert, and the rate at which you 
transmit or store.

I think there is great merit in sampling at 192k/s. These days a 192k/s 
24 bit stereo DAC offers excellent noise and distortion specs, and costs 
20 cents. Such a high sample rate really makes the analogue filtering a 
lot easier. A 192k/s ADC is not much more expensive (a difference 
probably driven more by volume than complexity).

Actually transmitting and storing such sample rates makes no sense at 
all. 44.1k/s was a bit marginal, when you allow for the impracticality 
of the filters getting really close to 0.5fs. However, 48k/s should be 
good enough for any practical purpose.

For people who say supersonic sound can't play a part in a listening 
experience, trying being in a room with a high intensity of supersonic 
energy. Under some conditions (I'm not clear which) you can sense it, 
even though you can't hear it. It actually feels like something loud 
that you can't hear is going on. Its a very odd feeling. That said, I've 
never found any evidence that this plays a part in any musical 
experience. I see no reason to try to capture that energy in a 
recording, unless you feel your dog should enjoy a greater musical 
experience.

Steve

In article <481becfe$0$5141$4c368faf@roadrunner.com>,
Green Xenon [Radium] <glucegen1@excite.com> wrote:
>Hi:
>
>Why does DVD-Audio use 192 kHz sample rate? What's the advantage over 
>44.1 kHz? Humans can't hear the full range of a 192 kHz sample rate?
>
>On average, what is the minimum sample rate for a guy in his early to 
>mid 20s who likes treble?

In my personal opinion, a rate of 192 kilosamples/second (allowing a
passband of DC to 96 kHz) is indeed overkill as an audio delivery
standard.

There may be _some_ justification for it, as it eliminates the need to
place the knee of the anti-aliasing filter anywhere near the range of
frequencies that one _can_ hear.  One of the criticisms made against
CD is that the sharp filtering which must be done at around 20 kHz can
cause artifacts which may be audible to some listeners, either due to
"pre-ringing" (with a symmetric FIR low-lass filter) or a frequency-
dependent delay and "smearing" of transients (with an IIR filter).

These effects can be moved up to higher frequencies, and prevented
from having effects in the human hearing passband, by increasing the
sampling rate.

My own personal guess is that a rate of 96 ksamples/second is probably
high enough to move any phase-affecting artifacts up well out of the
human hearing range, and that there are few if any benefits to going
to a rate higher than this.

>So whats the justification fur using 192 kHz? If you ask me, its just a 
>total waste of bandwidth and energy.

The likely reasons are twofold:

-  The "numbers game".  "More is better", at least in advertising
   literature.  The consumer-electronics company needed a New Big Thing
   to sell a new generation of products (everybody already had CD) and
   the media companies needed a New Better Delivery Platform to
   convince everybody to buy new editions of music they already own
   ("... have to buy the White Album again!" per Men In Black).
   Having an extremely high sample rate makes the new system sound
   even more attractive to the naive consumer.

-  The "why not?" issue.  The DVD storage technology has lots of
   space and bandwidth available, as it was designed for video.
   Storage space on the discs is not an issue... one could use an even
   higher rate than 192k, store a 90-minute album per disc, and still
   have space left over.  
   
>Please correct me if I'm wrong but AFAIK, its a waste of time, money, 
>energy to move to 192 kHz.

Given that DVD is used as the storage system, the costs of using such
a high data rate are negligible.

-- 
Dave Platt <dplatt@radagast.org>                                   AE6EO
Friends of Jade Warrior home page:  http://www.radagast.org/jade-warrior
  I do _not_ wish to receive unsolicited commercial email, and I will
     boycott any company which has the gall to send me such ads!