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In Search Of Accurate Sound Reproduction: The Final Word!


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3 hours ago, esldude said:

 

I have no argument with the results as they are.  The extra steep filtering yes.  Why?  Because if we relax the filter that was just barely detected to 1000 hz transition does the audibility of it go away?  I don't know, it seems a likely conclusion it might go away at some point.  It is telling that no testing at a 2050 hz transition was done.  Suppose that indicated the issue disappears? 

 

Great points. I agree it will go away at some point. But at what point requires speculation. By the way, if their filter is indeed unusual (haven't seen support for this, but let's go with it), your questioning the direct applicability to CD is relevant. But it is also interesting to consider what their data does tell us (not just what it may not tell us). It tells me that the cutoff of the filter can be too steep. As you ask: what is too steep? Many critics of the value of relaxed filters that higher sample rates allow, argue that whatever a steep filter does (phase is all I can think of, is there more?), it is inaudible. "Whatever" does seem to be audible (at least under the strict conditions you listed).

 

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Should we completely alter the audio world of music formats for the audiophile equivalent of 4 minute milers?  If so what would be required? Raising the sample rate to 65 khz and start using a transition zone of 7500 hz would do it.  Or simply using existing 88 khz or 96 khz rates would do it.   Pretending that either of those would benefit most audiophiles would be wishful thinking or maybe sensible overkill for certainty.

No, is anyone suggesting that? Right now there are so many formats available (lets say N), I don't think adding one more (e.g. MQA), which results in N+1 formats, constitutes completely altering the audio world of music formats, do you?

I don't think MQA will alter much, but I could be wrong. I think people will vote with their wallets. Personally, I don't really care about the real or illusory audible differences. Since it is proprietary, I won't buy it.

I like the phrase "sensible overkill for certainty"... of course defining that just starts another argument.

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1 hour ago, SoundAndMotion said:

Many critics of the value of relaxed filters that higher sample rates allow, argue that whatever a steep filter does (phase is all I can think of, is there more?), it is inaudible. "Whatever" does seem to be audible (at least under the strict conditions you listed).

Passband ripple is another filter characteristic that could possibly be relevant. With a 20 kHz cutoff, it does extend into the audible region. Of course, for any reasonable filter, this ripple is far smaller than the variations from speakers and room effects.

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51 minutes ago, mansr said:

Passband ripple is another filter characteristic that could possibly be relevant. With a 20 kHz cutoff, it does extend into the audible region. Of course, for any reasonable filter, this ripple is far smaller than the variations from speakers and room effects.

Yes, but in the Jackson paper it was set to +/- 0.025dB, so it seemed unlikely. I asked about phase more as an aside. Whether passband ripple, audible-range phase deviation or mutantly unmasked bat genes is a fun speculation to try to figure out the "whatever". But no matter the reason, it is audible.

A relevant question is whether that audibility is important. I doubt I could hear it and even if I could, I don't find it important to me. But I can't speak for others...

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9 hours ago, mansr said:

And here's the measured frequency response of that CD player:

d-50-fr.thumb.png.60a0a172a8071c00ba6ae65ebcb6ad62.png

 

It's a complex filter, several RC sections, two active parts and a band-pass with 3 inductors: not one for the purists!

Interesting graph, if real! It appears to show a level reduction from -78.5dB to -105dB which appears to be a full 26.5dB cut, which is marvellous.

 

AJ, thanks for the details where I can converse with this chap you've heard of who may have mentioned a transparent (glass, Lexan?) filter for the 44.1 that no one uses, I'm grateful to your references on this but I think that would be giving work to me to prove your assertions, which I don't agree with: so I'm not sure what would be in that for me. Any ideas?

 

It's interesting that as the CD fades into obscurity (This is COMPUTER audiophile, not OLD-CD-PLAYER audio right?) people desperately fighting to defend 16/44.1 become less able to justify why they do it. The filtering is largely solved with a simple up-tick in sample rate to 96 (or even 192) so I can't see the big retro attraction.

 

Additionally 16/44.1 is not the end of the processing chain today either, any digital room E.Q. or level control can only be described as Digital Signal Processing (DSP) which is far better done in 24 bits. Picture a speaker with a 3 way digital crossover feeding some class D chip amps glued to the back of the drivers, the obvious link then is a direct digital feed from your computer/device. 16/44.1 does nothing to help the sound quality here, it is just a tired remnant of a rather poor format that was needed 30 years ago because tech was a lot slower and smaller then. Every DSP devices first action on meeting a 44.1/16 format is then to escape from that format in much the same way it would deal with an MP3, decode it, guess the missing values and then process it.

 

So in a thread about accurate sound reproduction (which should probably include room correction) I find it disturbing that people are still living in the past clutching their obsolete favourite format despite the fact that decent formats are not only attainable but already used widely outside the 'HiFi' audio sector.

 

Crazy.

 

Battling the Loudness War with the SeeDeClip4 multi-user, decompressing, declipping streaming Music Server.

 

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23 minutes ago, CuteStudio said:

It's a complex filter, several RC sections, two active parts and a band-pass with 3 inductors: not one for the purists!

Nobody ever said it was simple. Quite the opposite, in fact.

23 minutes ago, CuteStudio said:

Interesting graph, if real! It appears to show a level reduction from -78.5dB to -105dB which appears to be a full 26.5dB cut, which is marvellous.

Of course it's real. I measured it myself. The player may be 35 years old, but it's still in perfect working order.

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5 hours ago, SoundAndMotion said:

I didn't say anything about audibility of >20kHz,

Right, the article Bob Stuart cited and I then referenced in this thread did, as supporting MQA.

The article by Stuart that you then cite is your "proof" that >20k filtering is audible

What do you call the "cut off" signal that the Kuribayashi article is comparing vs the >20k signals as being "inaudible"?

 

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By the way, citing an article does not mean supporting everything in it. You are very focussed on a few adjectives (inaudible, etc.), but I suspect Stuart cited the article for the data, not every word therein.

"The data" that says what in support of MQA? That it is inaudible???

Figure-2.png&key=87d12306dbf810c42d44f20

"Sound" Quality???

Hmmm

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On 6/19/2017 at 6:33 PM, CuteStudio said:

The need to do this appears to corroborate my initial (oddly controversial) contention that anti aliasing filters don't work (very well) on the 44.1kHz redbook standard.

 

On 6/19/2017 at 7:04 PM, AJ Soundfield said:

Evidence please.

Assuming even for a moment you mean "audible", please present contrary Redbook filter data to this http://www.aes.org/e-lib/browse.cfm?elib=15249

 

I answered this. I pointed out that M&M is flawed and your request for a counter to it would be Jackson. All anchored to CuteStudio’s concern that the filters “don’t work very well”. I took your cue to talk about audibility.

 

I did not answer the compilation of all your posts, just the one above and your replies to my posts.

 

I did not read Kuribayashi. I’m not interested and it was not relevant to my posts. I only mentioned that your getting excited about a few words in it and attempting to slam Stuart for citing it was nonsense. Otherwise I can use all the flaws of M&M to slam you since you cited them. Equally ridiculous.

 

I don’t care about Bob Stuart; that’s you. I don’t care about MQA; won’t be buying any. I don’t care about Kuribayashi’s data; I assumed (oops, sorry if I was wrong) that Stuart liked it and therefore cited it.

 

I was only answering the issues about audibility of the filter in the Jackson paper, which indicates a potential problem in Redbook filtering. I conceded that a different filter steepness may well be inaudible, but I haven’t seen evidence. M&M is too flawed.

 

This back and forth with you has not moved forward and is boring. I’m done with this line of discourse. You can have the last word. If it moves forward, I’ll read it and see if I can contribute.

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41 minutes ago, SoundAndMotion said:

I was only answering the issues about audibility of the filter in the Jackson paper, which indicates a potential problem in Redbook filtering. I conceded that a different filter steepness may well be inaudible, but I haven’t seen evidence.

Where is the evidence that the filter they concocted in MATLAB is "Typical"??

Here, let's remind you: The Audibility of Typical Digital Audio Filters in a High-Fidelity Playback System

Where does the burden of proof lie with that? How many different slope filters were tested?

How is it a  potential problem in Redbook filtering, if the filter used is pathological, with no evidence provided of any real filter used for Redbook, worse without standard best practices use TPDF? Did you read the comments section on AES for the paper?

What exactly does this "award winning" to quote your characterization, paper show regarding Redbook reality for consumers? Or does that even matter....

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1 hour ago, SoundAndMotion said:

This back and forth with you has not moved forward and is boring. I’m done with this line of discourse. You can have the last word. If it moves forward, I’ll read it and see if I can contribute.

 

Looks like

 

21 hours ago, AJ Soundfield said:

You win!

 

no more...

 

x-D

"Science draws the wave, poetry fills it with water" Teixeira de Pascoaes

 

HQPlayer Desktop / Mac mini → Intona 7054 → RME ADI-2 DAC FS (DSD256)

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On 6/21/2017 at 0:06 PM, mansr said:

Of course it's real. I measured it myself. The player may be 35 years old, but it's still in perfect working order.

 

Ah excellent, I wondered where it came from, hadn't realised you'd measured it. Cool!!

 

So I noted it seems to have about a full 26.5dB cut, but if I look at the 22.05 position (as close as I can) it looks to be only about 13.25dB down at the point, rather than the required 96dB, can you confirm that the vertical scale is in dB?

 

35 years and still going is good, obviously a quality piece of kit!

Battling the Loudness War with the SeeDeClip4 multi-user, decompressing, declipping streaming Music Server.

 

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6 minutes ago, CuteStudio said:

So I noted it seems to have about a full 26.5dB cut, but if I look at the 22.05 position (as close as I can) it looks to be only about 13.25dB down at the point, rather than the required 96dB, can you confirm that the vertical scale is in dB?

Yes, it's dB.

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On 6/21/2017 at 0:37 AM, AJ Soundfield said:

no one can build a 44.1k filter

 

Hi AJ, yes, that's what I was saying, I'm glad you have finally accepted the limitations of real world analog filters, although that particular one WAS real, I'm impressed with mansr's ability to pop up with a schematic + real measurement. It's an impressive filter but as you noted; it still appears to be a little over 82dB short of the target.

 

If you can post up any evidence to support your earlier assertion that real 44.1k filters are possible that'd be great, TIA. BTW interesting anecdote about the French Suite No. 5 by J. S. Bach.

Battling the Loudness War with the SeeDeClip4 multi-user, decompressing, declipping streaming Music Server.

 

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15 minutes ago, CuteStudio said:

it still appears to be a little over 82dB short of the target.

What target? What does that have to do with a 44.1k filter? Sorry if I can't quite keep track of all your hallucinations.

 

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If you can post up any evidence to support your earlier assertion that real 44.1k filters are possible that'd be great

See the fake one Mansr posted.

 

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BTW interesting anecdote about the French Suite No. 5 by J. S. Bach.

Glad you enjoyed it and the one with the red polo shirt with elephants

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2 hours ago, AJ Soundfield said:

What target? What does that have to do with a 44.1k filter?

Ah I see, this explains a lot of your earlier posts.

 

Allow me to educate you: In order to avoid aliasing errors the 44.1k filter is required to have a cut of around 96dB between 20k and 22.05kHz

 

Mansr very usefully posted not only a schematic but actual measurements of his D50's filter that showed that it was possibly to get within about 85dB of the target using quite a complex filter, which was interesting.

 

We are waiting for you to produce evidence of an anti-aliasing filter that cuts 20k to 22.05kHz by 96dB to support the outlandish claim that a filter was possible.

 

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hallucinations.

I'm sorry to hear about those, everyone has problems, no need to air them here.

 

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See the fake one Mansr posted.

What makes you think mansr posted anything fake? He's made the best contribution so far!

 

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Battling the Loudness War with the SeeDeClip4 multi-user, decompressing, declipping streaming Music Server.

 

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7 minutes ago, CuteStudio said:

There are two major issues with redbook:

441.kHz. No one can build a "real" filter that works for that

 

We are waiting for you to produce evidence of an anti-aliasing filter that cuts 20k to 22.05kHz by 96dB to support the outlandish claim that a filter was possible.

"We" are?? Sorry sir, no direct access to your imaginations inside head, just your initial quote above.

Ok, now we have some externalization. Is this an academic question, or are you implying some audible consequence?

Need a better scale, but this looks close

212BM1fig04.jpg

 

 

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24 minutes ago, CuteStudio said:

I Always though a 96dB filter in 0.05kHz was impossible but I'm willing to learn!

 

We are waiting for you to produce evidence of an anti-aliasing filter that cuts 20k to 22.05kHz by 96dB to support the outlandish claim that a filter was possible.

Wait, I'm back to confused again, what are you asking now?

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19 hours ago, AJ Soundfield said:

this looks close

212BM1fig04.jpg

 

 

 

A 3.25dB cut is a little short of the 96dB required.

 

So Aj you are now reduced to something akin to a robot on Star Trek who Kirk has locked up with a logical dilemma, and just stands there, lights flashing, issuing intelligible gibberish.

 

Perhaps next time you'll think twice before casually dismissing statements that clearly exceed your limited knowledge and grasp of the subject. It's not even a slightly tricky one, it's been known for over 30 years that this anti-aliasing was impossible to build correctly, that's why everyone suddenly started upsampling: duh. 

 

Battling the Loudness War with the SeeDeClip4 multi-user, decompressing, declipping streaming Music Server.

 

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