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Topic: Audibility of "typical" Digital Filters in a Hi-Fi Playback  (Read 139066 times) previous topic - next topic
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Audibility of "typical" Digital Filters in a Hi-Fi Playback

Reply #675
This could indeed result in a huge fail for the hi-res peddlers.
By suggesting to the masses that it is the format that makes the music sound better instead of the recording, mixing and mastering "choices", the people responsible for the horrible sound quality would get a free pass for what, another decade, two, until ultra-hi-res comes along?

The rationale behind this is that by making hi-res a commodity just like the CD, the uninformed average listener will just happily buy a crappy hi-res product as he/she is doing today with crappy CDs. CD audio would become obsolete, hi-res crap the norm rather than the exception.

I can already imagine amirm in 10 years, still wasting Internet traffic, but this time about ultra-hi-res, and how bigger is always better (except if it doesn't fit his momentary argument).



We already have over a decade of anecdotal cases where the mere label "high resolution"  (sacd, dvd-a, bluray, HDtracks) is enough to send listeners into raptures.  In not a few of those cases, the source was analog tapes,  or SD PCM, or the mastering bears evidence of the 'loudness wars'. 

We also have cases where some recognize that they've been shucked -- the mastering doesn't live up to the high rez hype.

You get it.  2bdecided gets it.  We, generally, (at HA) get it: 'It's the mastering, stupid.'

The Dancing Man from Madrona *knows* it, but keeps dancing around it.  He has a commercial -- and hugely ego-based -- disincentive to acknowledge 'getting it'. 

Is it perhaps time to close the thread down?  Is there anything more to be expected from Amir than propaganda, diversion, obfuscation, nit-picking, and Arny-baiting? Is there anyone besides him who will take up the 'cause' of 'high rez' here?

I wonder. 

Audibility of "typical" Digital Filters in a Hi-Fi Playback

Reply #676
But you want to make CD obsolete, right?


He wants to make 'standard resolution' obsolete.  Because, well, "high rez"!

Now, a true 'audiophile' would want to make crappy recording and mastering and playback conditions obsolete.  They'd be pushing for mastering standards and for moving beyond the 2channel bottleneck.  "Hi rez" delivery formats, which cannot *necessitate* or *guarantee* any of these things,  and which provide miniscule audible improvements over SD only when listened with certain abnormal preconditions, would be a minor little side-skirmish in a much larger battle to render crap sound obsolete.

But instead.....

Audibility of "typical" Digital Filters in a Hi-Fi Playback

Reply #677
Addressing this bit of pseudo science:
1. Where on earth do you see non-linear distortions? You don't even know what an LTI system is, but talk big about filters? What the..

Down conversion involves both filtering and quantization.  Quantization error is anything but a linear distortion.


But quantization error is a non-problem given that the down conversion is properly dithered. The means for effecting proper dither (TPDF dither of sufficient amplitude best practice being perceptually shaped PSD) has been a solved problem for everybody with a brain (except the perpetrators of the recent Meridian fiasco who used RPDF dither - oops!) for decades.

Sorry Amir, but this is just a diversion off-topic that could be legitimately discussed in another thread, but not here.

Audibility of "typical" Digital Filters in a Hi-Fi Playback

Reply #678
When he was invited to sit on Ludwig’s Platinum Mastering Panel this year, Doug Sax suggested they discuss mastering for multiple formats. “Ten years ago, you made a CD master and you were done,” Sax says. “Now you do a CD master, a master for iTunes, a high-resolution master for HDtracks, and a cutting master for vinyl.”

See? Separate mastering. You think he is going to do the same thing he does for iTunes? or CD? He doesn't or he wouldn't have specifically named that as another branch.
It isn't clear if Sax meant individual "mastering" or creation of delivery formats.
Mastering usually consists of two steps: a creative one where the rough audio material is analyzed and (hopefully) improved by applying EQ, dynamic range compression and any other techniques to make it sound better for the intended purpose. IME the final result is captured in a hi-res format and downconverted by using trusted tools. Ideally every non-losslessly converted format should be auditioned by a qualified engineer.
The second step is the creation of delivery formats, which is the non-creative part. Entering meta-data like PQ, ISRC, EAN, cd-text etc. This is important, time consuming but less critical work and is often done by assistant engineers.
Having done quite some mastering I can attest that multiple delivery formats require more work and consequently increase the invoice for the client.

Audibility of "typical" Digital Filters in a Hi-Fi Playback

Reply #679
When he was invited to sit on Ludwig’s Platinum Mastering Panel this year, Doug Sax suggested they discuss mastering for multiple formats. “Ten years ago, you made a CD master and you were done,” Sax says. “Now you do a CD master, a master for iTunes, a high-resolution master for HDtracks, and a cutting master for vinyl.”



Doug Sax endorsed Shakti Stones.

I would classify him with the cohort of mastering 'engineers' who, having learned how to make great recordings, think that everything they hear is real.

Audibility of "typical" Digital Filters in a Hi-Fi Playback

Reply #680
We hear each one of those samples as they come. The brain doesn't collect them all and then say, "ah, that was a FIR filter."
The purpose of the BS paper was (or at least should have been) to find out IF those samples make it at all to the brain. In theory those samples are supposed to be inaudible. That's why listening tests which indicate otherwise should be analyzed very carefully.

Audibility of "typical" Digital Filters in a Hi-Fi Playback

Reply #681


From math/signal processing point of view we can say all of this ringing is benign.  The theory says this is what must hear the in time domain to implement the low pass function.  But that is not how the psychoacoustics works.  We hear each one of those samples as they come.  The brain doesn't collect them all and then say, "ah, that was a FIR filter."  It hears the individual samples as they get processed by the transfer function of the low pass filter.  This is why you can't use your logic of "it is a linear function."  Those sample transforms taken individually do not represent such.

Sorry, but as written this is very misleading. The response shown is that of a digital FIR filter. In whole or in part, it is a linear transform, down to the arithmetical limits of the DSP. Such limits were 120dB down a couple of decades ago. You talk about hearing this. I am not convinced.

Cheers,
David.

Audibility of "typical" Digital Filters in a Hi-Fi Playback

Reply #682
Addressing this bit of pseudo science:

Let me refute your own words by using your own words:

---

Down conversion involves both filtering and quantization.

First:
Let's start at the top.  This is the title of the paper:The audibility of typical digital audio filters in a high-fidelity playback system

No, I am not being pedantic .  Please pay attention to what I have highlighted: digital audio filters.  That is the mission of the paper.  They start with 192 Khz music samples, then apply two filters to it.  One is to represent CD sampling rate of 44.1 Khz and the other, 48 Khz.  Here is the paper itself in technicolor to make sure these key points are not lost:

2.3. Signal processing and test conditions

Two kinds of linear-phase FIR (fnite impulse re-
sponse) filter were used, both of which operated at
192 kHz and both of which were implemented us-
ing TPDF (triangular probability density function)

dither at the 24th bit.

Secondly:

"prefect linearity"
Oh no, it looks like your authorities have betrayed you.
As I said, you don't understand what you're talking about.

---

Do you really think what they heard in Stuart's listening test was linear distortion?  Linear distortion garners such adjectives?  "Echoes, when audible, were identi ed as being a ected the most clearly by the ltering. It was felt that some of the louder passages of the recording were less aggressive after ltering, and that the inner voices (second violin and viola) had "a nasal quality".  I don't think so.  Not at all.

Here's what you wrote to the objection of worse RPDF before:
But go ahead and move the green line up 6 db if it makes you feel better. It is still below the threshold of hearing.

Remember, you will lose a much larger battle if you stay on this path Arny.  That such noise levels is audible in a 105 db SPL playback.  And that they are so audible as to be an obvious flaw in the test.

So keep going at your peril.

Here you first say that even the worse 16-bit RPDF is not audible, but a few pages later you seriously claim that 24-bit TPDF causes audible non-linear distortion.

---

And finally, a quote for the LOLs that doesn't need further comment:
Let's look at the impulse response again:
[...]
We hear each one of those samples as they come.  The brain doesn't collect them all and then say, "ah, that was a FIR filter."  It hears the individual samples as they get processed by the transfer function of the low pass filter.  This is why you can't use your logic of "it is a linear function."  Those sample transforms taken individually do not represent such.

And to make this even more funny:
To understand this topic fully, you must have broad understanding of multiple disciplines.



Listen to this 4 second short test file: imp_urhp.wav, and tell us what you hear in your system.


No, the war has been lost.

Take your meds amir, there is no war. And stop refuting and contradicting and embarrassing yourself ... even more.
"I hear it when I see it."

 

Audibility of "typical" Digital Filters in a Hi-Fi Playback

Reply #683


From math/signal processing point of view we can say all of this ringing is benign.  The theory says this is what must happen in time domain to implement the low pass function.


False claim. The above appears to be the response of a linear phase low pass filter to an impulse. However all low pass filters are not linear phase. For example a low pass filter can be minimum phase in which case there is no pre-ringing.

Quote
But that is not how the psychoacoustics works.  We hear each one of those samples as they come.


Not on the planet earth, not if the listener is a human being, and not if the sample rate is much higher than a few 100 Hz at the most.

A good reference in this matter is found here: http://www.aes.org/sections/pnw/ppt/jj/fund_of_hearing.ppt

"The inner ear is a mechanical filter bank, implementing a filter whose center-frequency tuning goes from high to low as one goes farther into the cochlea"

in short the stimulus that the brain responds to is the spectral content of the sound, not any imagined sample-by-sample analysis of digital data clocked in the 10s of KHz.

The above are two unbelievably poorly informed comments, especially given the alleged credentials of its author, and the fact that he has quoted the document I just referenced in this thread very recently.

Audibility of "typical" Digital Filters in a Hi-Fi Playback

Reply #684
False claim. The above appears to be the response of a linear phase low pass filter to an impulse. However all low pass filters are not linear phase. For example a low pass filter can be minimum phase in which case there is no pre-ringing.

That's not even the problem of his momentary claim (he changes them whenever he sees fit). To justify his repeated false comment about non-linear distortion in filters (that's what we were talking about) he had to go back to quantization, which he himself discarded before in this thread as being an audible problem - and that was with noise-modulating 16-bit RPDF.

"I hear it when I see it."

Audibility of "typical" Digital Filters in a Hi-Fi Playback

Reply #685
False claim. The above appears to be the response of a linear phase low pass filter to an impulse. However all low pass filters are not linear phase. For example a low pass filter can be minimum phase in which case there is no pre-ringing.

That's not even the problem of his momentary claim (he changes them whenever he sees fit). To justify his repeated false comment about non-linear distortion in filters (that's what we were talking about) he had to go back to quantization, which he himself discarded before in this thread as being an audible problem - and that was with noise-modulating 16-bit RPDF.





I think that cat is who one becomes if one gives too much credibility is given to the wrong people.

There is an old saying: Engage brain, then open mouth. 

Truth be known everybody fails to follow this procedure every once in a while. The procedure seems to be absent or suspended permanently in some cases, eh? ;-)

Audibility of "typical" Digital Filters in a Hi-Fi Playback

Reply #686
Why aren't we discussing the BS paper and what they claim to have heard, instead of some subjectivist audiophile with a long history of absurd GE claims about hearing (via "listening") linear vs SMPS, SPDIF cables, DACs with +/-10% volume methodology, class d filtering, power regenerators, etc, etc, etc?
Last I checked, Amir was not present for the BS tests and was not part of that supervised listening panel (or any other, recorded, ever). He is not mentioned anywhere in the BS paper, which is purportedly the thread topic.

cheers,

AJ
Loudspeaker manufacturer

Audibility of "typical" Digital Filters in a Hi-Fi Playback

Reply #687
Quote

In comparison testing I have done, switching amplifiers using the classic class D configuration always sport incredible low frequency control and power. They beat out linear class AB amplifiers almost regardless of price. What they give up though is high frequency fidelity which I find somewhat harsh. The distortion is highly non-linear and challenging to spot but it is there. The Mark Levinson No 53 is the first switching amplifier I have heard which does not have this compromise. Its bass is amazingly authoritative: tight and powerful. Yet the rest of the response is absolutely neutral and pleasant.

If you have not heard these unique amplifiers, I highly encourage you to come into our showroom for a listen. We have a pair on hand driving our Revel speakers. I am confident that they will improve the sound of your current speakers given the ease with which they can drive any load regardless of how difficult they might be (and many high-end speakers are difficult to drive). We are happy to let you evaluate them with your own system to see the benefits of this technology. Hearing this amplifier was an eye-opener for me. I think it will be for you too.


 


Can anybody explain to me how to distinguish the above 2 paragraphs from the usual subjectivist false claims that we all know and find to be unfounded, senseless and reprehensible?

Audibility of "typical" Digital Filters in a Hi-Fi Playback

Reply #688
Quote
But that is not how the psychoacoustics works.  We hear each one of those samples as they come.


Not on the planet earth, not if the listener is a human being, and not if the sample rate is much higher than a few 100 Hz at the most.

A good reference in this matter is found here: http://www.aes.org/sections/pnw/ppt/jj/fund_of_hearing.ppt

"The inner ear is a mechanical filter bank, implementing a filter whose center-frequency tuning goes from high to low as one goes farther into the cochlea"

in short the stimulus that the brain responds to is the spectral content of the sound, not any imagined sample-by-sample analysis of digital data clocked in the 10s of KHz.

Really?  Here is the other JJ ES presentation I referenced earlier which you said you had read and were quoting sections from it:

.

This is why I say this discussion is not about science.  Science would require someone to well, study science .  When Arny says he has read about a topic and the very same presenter has said the opposite of what he is saying, and said reference was available to him just yesterday, then this is not a scientific discussion.  It is the Xbox vs Playstation argument by two 16 year old that don't know a GPU from an FPU. 

The notion that people with no educational or professional experience in the field waking up in the morning and post technical statements on a complex topic like this being a scientific approach requires suspension of disbelief.  Somehow we have fooled ourselves into thinking getting our knowledge from forum posts and googling, and being loud means we are discussing "science."  That is not remotely a possibility in real life.

That is on top of scientific method requiring unbiased approach to all data which is anything but what we are seeing here.

Quote
The above are two unbelievably poorly informed comments, especially given the alleged credentials of its author, and the fact that he has quoted the document I just referenced in this thread very recently.

Right... The very powerpoint I just quoted above which 100% disputes your read of the topic.
Amir
Retired Technology Insider
Founder, AudioScienceReview.com

Audibility of "typical" Digital Filters in a Hi-Fi Playback

Reply #689
Quote
But that is not how the psychoacoustics works.  We hear each one of those samples as they come.


Not on the planet earth, not if the listener is a human being, and not if the sample rate is much higher than a few 100 Hz at the most.

A good reference in this matter is found here: http://www.aes.org/sections/pnw/ppt/jj/fund_of_hearing.ppt

"The inner ear is a mechanical filter bank, implementing a filter whose center-frequency tuning goes from high to low as one goes farther into the cochlea"

in short the stimulus that the brain responds to is the spectral content of the sound, not any imagined sample-by-sample analysis of digital data clocked in the 10s of KHz.

Really?  Here is the other JJ ES presentation I referenced earlier which you said you had read and were quoting sections from it:



It is exactly what I said.  That the ear analyzes samples in time.


Amir, it would be nice if your revisionist history were accurate. However you didn't say what you are now claiming. You said:

"We hear each one of those samples as they come."

And speaking of revisionism, JJ actually said:


"It (the ear) does not wait for the whole filter to arrive."

So, how many samples long is a 44 KHz reconstruction filter?

For your claim: ""We hear each one of those samples as they come." to be relevant, every 44 KHz reconstruction filter would have to be just one sample long.

Reality is that these filters are from dozens to 100's of samples long.  All JJ said was that our ears don't have to wait for the whole lot of from dozens to 100s of samples to arrive in order to start perceiving how the audio signal sounds.

There's a built in common sense reality check here. What kind of discrimination does the ear have over music samples that are one or two samples long?  Can you name that tune in 25-50 microseconds?  Of course you can't!

So its fail, fail, fail.  First we have the pair of ludicrous errors, and then we have the purported support for the ludicrous errors based on grotesque misunderstandings and utter distortion of the meaning and sometimes even the actual contents of the quoted or paraphrased portions of the references.

If this were a high school debate what would the judges do if a high school student resorted to these tactics?  I don't know because I've never seen a high schooler screw up this badly.


Audibility of "typical" Digital Filters in a Hi-Fi Playback

Reply #690
Why aren't we discussing the BS paper and what they claim to have heard, instead of some subjectivist audiophile with a long history of absurd GE claims about hearing (via "listening") linear vs SMPS, SPDIF cables, DACs with +/-10% volume methodology, class d filtering, power regenerators, etc, etc, etc?
Last I checked, Amir was not present for the BS tests and was not part of that supervised listening panel (or any other, recorded, ever). He is not mentioned anywhere in the BS paper, which is purportedly the thread topic.

cheers,

AJ
In the context of the paper, apparently the actual snippets from the musical selection are not going to be made available due to copyright concerns. Further the 192 kHz would simply be too large to email. This means that in the context of the BS paper there is no way to examine/evaluate/whatever the actual selections used. However the good news is that headphones, even if they don't extend to 40kHz should be adequate but then you'd have to create your own snippets.

Audibility of "typical" Digital Filters in a Hi-Fi Playback

Reply #691
Sorry, but as written this is very misleading. The response shown is that of a digital FIR filter. In whole or in part, it is a linear transform, down to the arithmetical limits of the DSP. Such limits were 120dB down a couple of decades ago. You talk about hearing this. I am not convinced.

I didn't talk about "hearing this."  As in "this" being a specific thing.  As I keep saying, the nature of ABX tests is not qualitative.  And at any rate, the tests I performed were combination of filtering and quantization which is not a linear transform.  Distinguishing files or even observing subjective difference doesn't spit out the cause.

Stuart's listening tests however does examine "this" to fair extent.  They isolated just the filter and tested its audibility and got positive outcome to statistical confidence.  And they were not searching down in 120 db SPL.  They compared filter lengths between 44 and 48 Khz and hypothesized the difference in audibility to filter length.  Clearly none of their subjects was hearing the extended ultrasonic response in frequency domain between 22 and 24 Khz.

As I just correct Arny, JJ's slide very clearly confirms the same that the brain is not a DSP machine where it captures a bunch of samples and then decides what it means.  Note how JJ wrote that in capital letters.  And this was my key point to xnor.  That he can't use DSP explanations to rule out audibility.  The brain's model of perception does not match the mathematical model of filter transforms.  At the risk of stating the obvious, it can't hear the future!  It has to judge the samples as they arrive and modified by the filter coefficients.

So sure, we can have our doubts but we can't rule it out as impossibility based on combined science of signal processing and psychoacoustics as xnor attempted.

Edit: usual typos.
Amir
Retired Technology Insider
Founder, AudioScienceReview.com

Audibility of "typical" Digital Filters in a Hi-Fi Playback

Reply #692
I guess when jj talks about problems of ringing it is a problem especialy for lossy because the filters work near the audible band when cutting out masked content.
btw. i once saw nice pictures done with iZotope RX that shows the ringing together with its spectral distribution. Can anyone create one so that we don't have to look at this silly ringing picture the marketing uses since years?
Is troll-adiposity coming from feederism?
With 24bit music you can listen to silence much louder!

Audibility of "typical" Digital Filters in a Hi-Fi Playback

Reply #693
I guess when jj talks about problems of ringing it is a problem especialy for lossy because the filters work near the audible band when cutting out masked content.

No, the presentation is not about lossy compression.  He is using what he is hoping to be a familiar analogous problem in lossy compression as I did.  Here is the title of the presentation:



As you see, it is completely about the topic at hand.  I also showed the follow up slide where he directly got into its relevance to anti-aliasing filters.

Quote
btw. i once saw nice pictures done with iZotope RX that shows the ringing together with its spectral distribution. Can anyone create one so that we don't have to look at this silly ringing picture the marketing uses since years?

Not sure what is wrong with the picture but here is JJ's:

Amir
Retired Technology Insider
Founder, AudioScienceReview.com

Audibility of "typical" Digital Filters in a Hi-Fi Playback

Reply #694
As I just correct Arny, JJ's slide very clearly confirms the same that the brain is not a DSP machine where it captures a bunch of samples and then decides what it means.  Note how JJ wrote that in capital letters.  And this was my key point to xnor.  That he can't use DSP explanations to rule out audibility.  The brain's model of perception does not match the mathematical model of filter transforms.  At the risk of stating the obvious, it can't hear the future!  It has to judge the samples as they arrive and modified by the filter coefficients.

So sure, we can have our doubts but we can't rule it out as impossibility based on combined science of signal processing and psychoacoustics as xnor attempted.

Oh boy, it hurts so much.
After contradicting and refuting yourself on the non-linear distortion part, of course you have to switch topics again and in the process put words in my mouth, fighting a straw man in your imaginary war.

No samples arrive at the ear, as you said. The ear receives a continuous mechanical wave that oscillates. Of course the ear doesn't wait for specific filters to arrive, it would have to wait a few seconds if we use a long filter.
As you've quoted many times now, the problem with pre-ringing jj mentions primarily are filter banks in codecs that operate across the whole audible range. He even specifically gives the example of cutoff frequencies of 2 and 4 kHz.
As you send a short signal that contains energy from 1 to 3 kHz into a filter that cuts off at 2 kHz, the pre-ringing at 2 kHz will build up slowly until it reaches the point where most energy is concentrated in the filter. This 2 kHz ringing can be audible.

I do not see how this is so had to get. Even a child should understand that ringing (which can be reduced or even eliminated, see previous posts) outside the hearing range is different from clearly within the hearing range.


I also asked you to listen to a 4 second short test file for like ~20 times now, to shed some light on what you hear in your system.
Are you afraid to tell us? What's wrong amir?
"I hear it when I see it."

Audibility of "typical" Digital Filters in a Hi-Fi Playback

Reply #695
These are pictures of impulse and frequency response. Nothing to wurry about.
Is troll-adiposity coming from feederism?
With 24bit music you can listen to silence much louder!

Audibility of "typical" Digital Filters in a Hi-Fi Playback

Reply #696
Stuart's listening test showed audibility of such

Bzzzt, wrong. Impossible for you to be cognizant of this, but this is both a causal and wishful thinking fallacy.
You have no clue what the cause is for what the BS test claims, whether it was system artifacts - speakers, switching software, time alignment, level alignment, frequency response in-band, etc, etc. or just the "emulated" filter/doctored dither.

cheers,

AJ
Loudspeaker manufacturer

Audibility of "typical" Digital Filters in a Hi-Fi Playback

Reply #697
No, the presentation is not about lossy compression.  He is using what he is hoping to be a familiar analogous problem in lossy compression as I did.  Here is the title of the presentation:

You seriously cherry-pick the title of a presentation over the actual content of the actual slide you were just talking about a moment ago? You even highlighted CODECS yourself.

Wow... I'm speechless.

amir credibility = 0
"I hear it when I see it."

Audibility of "typical" Digital Filters in a Hi-Fi Playback

Reply #698
No, the presentation is not about lossy compression.  He is using what he is hoping to be a familiar analogous problem in lossy compression as I did.  Here is the title of the presentation:

You seriously cherry-pick the title of a presentation over the actual content of the actual slide you were just talking about a moment ago? You even highlighted CODECS yourself.

Wow... I'm speechless.

amir credibility = 0

This is the slide again:

.  No on this planet as Arny would say. And the "two examples" that followed?  They were two antialiasing filters, one with gentle and the other with sharp response.  As I explained to Wombat, he is using pre-echo in codecs as a similar problem that is "hard to solve."

He also specifically talks about "converters" having pre-echo.  Converters have nothing to do with codecs.  That is the last letter in DAC/ADC.

You clearly can't follow technical explanations.  Even a layman would see that you read the slide and presentation topic wrong.
Amir
Retired Technology Insider
Founder, AudioScienceReview.com


 
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