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Official Classe SSP-800 thread. - Page 52

post #1531 of 5778
Quote:
Originally Posted by Roger Dressler View Post

Sorry for my misunderstanding. Jim "Oddiophile" pasted some good info about it here, in the parallel universe.

So, to answer your question, no, apodising filters are not like tone controls. It is a means to "de-ring" the source audio, removing the smear caused by anti-alias filters, particularly as used for 44.1 and 48 kHz sample rates. The resulting audio is 88.2 or 96 kHz, and sounds remarkably as if it were recorded at that rate from the start.

sent an email to dave to ask his thoughts on it. Is it supported by the DSP or would they have to wait for it to be supported?
post #1532 of 5778
Quote:
Originally Posted by sikoniko View Post

sent an email to dave to ask his thoughts on it. Is it supported by the DSP or would they have to wait for it to be supported?

They'd have to cook their own or have it developed for them by a third party. It's not a stock algorithm from MDS or the usual licensors.
post #1533 of 5778
Quote:
Originally Posted by Roger Dressler View Post

Sorry for my misunderstanding. Jim "Oddiophile" pasted some good info about it here, in the parallel universe.

So, to answer your question, no, apodising filters are not like tone controls. It is a means to "de-ring" the source audio, removing the smear caused by anti-alias filters, particularly as used for 44.1 and 48 kHz sample rates. The resulting audio is 88.2 or 96 kHz, and sounds remarkably as if it were recorded at that rate from the start.

I found this response to the AV Guide Meridian player review interesting. Thoughts?

Quote:


Regardless, the phase alterations, frequency limitations and ringings introduced by speakers and the listening room are arguably orders of magnitude larger than what any CD player may or may not do.

Have you heard a player with one of these apodising filters? Was it really the night and day difference stated in the AV Guide review?
post #1534 of 5778
Quote:
Originally Posted by hifisponge View Post

I found this response to the AV Guide Meridian player review interesting. Thoughts?

Yes, that response is laughably naive.

Quote:


Have you heard a player with one of these apodising filters? Was it really the night and day difference stated in the AV Guide review?

I was able to spend some quality time with the Meridian player, and my old friend Bob Stuart, at the Venetian suite at CES a couple years ago. He did not tell me until later that he was playing CDs--as I had assumed it was a DVD-Audio presentation as so many times before.

So the question is simply this--do 96 kHz recordings sound night and day better than CDs? Each person has their own answer to this question, spanning the gamut. I'd say those answers map directly to the apodising question.
post #1535 of 5778
Quote:
Originally Posted by Roger Dressler View Post

Yes, that response is laughably naive.

OK, good. It would be nice to have something in this hobby to look forward to.

Quote:


I was able to spend some quality time with the Meridian player, and my old friend Bob Stuart, at the Venetian suite at CES a couple years ago. He did not tell me until later that he was playing CDs--as I had assumed it was a DVD-Audio presentation as so many times before.

So the question is simply this--do 96 kHz recordings sound night and day better than CDs? Each person has their own answer to this question, spanning the gamut. I'd say those answers map directly to the apodising question.

Good answer. Much more meaningful than, "it kicks the crap out of CD", or "there is no difference".
post #1536 of 5778
So, Roger, if I were to want to determine if I hear a meaningful difference between 96 and 44.1, without getting to formal or scientific, could I take one of the 96KHz tracks I have stored on my music server (Mac computer), convert it to 44.1KHz and switch between the two?
post #1537 of 5778
Quote:
Originally Posted by hifisponge View Post

So, Roger, if I were to want to determine if I hear a meaningful difference between 96 and 44.1, without getting to formal or scientific, could I take one of the 96KHz tracks I have stored on my music server (Mac computer), convert it to 44.1KHz and switch between the two?

Basically, yes. You'll want to start with a 96kHz track that is known to be of high quality--open, airy, delicate, clean....

Also, you'd want to convert it to 48kHz (divide by 2 is computationally easier than divide by 2.176870748299...), and even then, I'm not sure that the downsampler in the Mac is of the same calibre as one finds in studios/mastering houses. So it may put the 48kHz version at some disadvantage.

If it turns out that you find no compelling difference between the 48 and 96 kHz versions, then case closed. If it turns out you hear an appreciable difference, I'm not sure you can attribute it solely to the sample rate, as the downsampler may have left its fingerprints.
post #1538 of 5778
Quote:
Originally Posted by Roger Dressler View Post

Basically, yes. You'll want to start with a 96kHz track that is known to be of high quality--open, airy, delicate, clean....

Also, you'd want to convert it to 48kHz (divide by 2 is computationally easier than divide by 2.176870748299...), and even then, I'm not sure that the downsampler in the Mac is of the same calibre as one finds in studios/mastering houses. So it may put the 48kHz version at some disadvantage.

If it turns out that you find no compelling difference between the 48 and 96 kHz versions, then case closed. If it turns out you hear an appreciable difference, I'm not sure you can attribute it solely to the sample rate, as the downsampler may have left its fingerprints.

Understood. So round in round one if I do hear a difference, further investigation may be needed because of the possibility that the the conversion process caused the difference. However, if I hear no difference, then there is little to no chance that I will appreciate what an apodising filter does.... and subsequently, I'll have my audiophile licenese revoked.
post #1539 of 5778
Quote:
Originally Posted by hifisponge View Post

Understood. So round in round one if I do hear a difference, further investigation may be needed because of the possibility that the the conversion process caused the difference. However, if I hear no difference, then there is little to no chance that I will appreciate what an apodising filter does.... and subsequently, I'll have my audiophile licenese revoked.

Zactly.

Just curious, have you formed any general conclusions based on your experiences with 96 kHz recordings vis a vis CD? Do they just sound like well mastered CDs, or do they seem to transcend even the best in some etheral way?
post #1540 of 5778
Quote:
Originally Posted by Roger Dressler View Post

Zactly.

Just curious, have you formed any general conclusions based on your experiences with 96 kHz recordings vis a vis CD? Do they just sound like well mastered CDs, or do they seem to transcend even the best in some etheral way?

My previous experience with DVDA and SACD was that they sound like well mastered CDs, but those were played through my old system (Paradigm Sigs and a Denon AVR and Denon player).

My SSP-800 had a bad optical digital board in it from the start that would not accept a 96KHz signal. I just got it back from repair last Friday, so I haven't had the chance to try out any of my 96KHz recordings.

First up for my listening test will be this:
http://www.computeraudiophile.com/Ke...gue-III-Review
post #1541 of 5778
Quote:
Originally Posted by hifisponge View Post

It will accept a 192kHz signal, but it down-rezes it to 96KHz. The DAC's in the 800 are capable of 192 output, but Classe found that the best performance from them was at 96. Think of it like running a car's engine at the red line on the tach vs. keeping it in the power band.

I received the 2L Audiophile Reference Recordings: The Nordic Sound [Blu-ray] and on the SSP-800 info it indicates the the sr=192. Just like to verify that this is showing the source and then down converting it to 96. I was listening to the Blue Ray disk and it also comes with a SACD disk. I know that I couldn't hear the difference between a sample rate of 96 and 192 anyhow. Just curious.
post #1542 of 5778
Quote:
Originally Posted by wcranston View Post

I received the 2L Audiophile Reference Recordings: The Nordic Sound [Blu-ray] and on the SSP-800 info it indicates the the sr=192. Just like to verify that this is showing the source and then down converting it to 96. I was listening to the Blue Ray disk and it also comes with a SACD disk. I know that I couldn't hear the difference between a sample rate of 96 and 192 anyhow. Just curious.


So? How is the disc? worth a purchase?
post #1543 of 5778
I am considering the Classe 800 in order to take advantage of the high-res audio on Blu-Ray. I have a 2-channel system using a Mark Levinson No. 380S preamp. I am wondering if anyone has any thoughts on whether this would be a step down in audio quality, at least with standard-res material. Any opinions would be welcome.
post #1544 of 5778
Quote:
Originally Posted by adidino View Post

So? How is the disc? worth a purchase?

Yes. It's a mix of many styles of music. String Quartet, Choral, Orch. Piano, etc. Basically, it's a sampler. Nothing Rock or Jazz related.
post #1545 of 5778
Quote:
Originally Posted by Quilty View Post

I am considering the Classe 800 in order to take advantage of the high-res audio on Blu-Ray. I have a 2-channel system using a Mark Levinson No. 380S preamp. I am wondering if anyone has any thoughts on whether this would be a step down in audio quality, at least with standard-res material. Any opinions would be welcome.

I haven't heard the ML 380S, but this quote from the recent AV Guide review of the SSP-800 may be of interest to you.

Quote:


One of the engineers who worked on this problem (and on many other aspects of the SSP-800) is Alan Clark, the primary author of the great Linn CD12 CD player. Clark is VP of Research and Development and Chief Technical Officer of the B&W Group. Another Classé engineer who contributed greatly to the SSP-800 is Tom Calatayud, who worked at Mark Levinson on such products as the groundbreaking No.30 digital processor and No.40 Media Controller.
post #1546 of 5778
Quote:
Originally Posted by wcranston View Post

I received the 2L Audiophile Reference Recordings: The Nordic Sound [Blu-ray] and on the SSP-800 info it indicates the the sr=192. Just like to verify that this is showing the source and then down converting it to 96. I was listening to the Blue Ray disk and it also comes with a SACD disk. I know that I couldn't hear the difference between a sample rate of 96 and 192 anyhow. Just curious.

Here's a quote from a thread on another forum that goes into detail about the 800's capabilities, which I believe was verified with Classe:

Quote:


All of the current sample rates including 7.1 channels at 192kHz/24-Bit are supported. However, the DAC systems perform best, with the lowest THD+N, when implemented as 96kHz input. Therefore, the SSP-800 will sample rate convert the signals to 96kHz before going to the DACs.

More here: http://htguide.com/forum/showthread....hlight=ssp-800
post #1547 of 5778
Quote:
Originally Posted by hifisponge View Post

I haven't heard the ML 380S, but this quote from the recent AV Guide review of the SSP-800 may be of interest to you.

Thanks!
post #1548 of 5778
Not to rain on anyones parade, but I heard back from Dave and the short answer on apodising filters is that they had considered it at one point but have decided that they can do better without it. Here is a direct quote:

Quote:


We’ve looked at apodising filters but do not think the trade off is worth it in our design. Although I’m sure you could make a good sounding DAC with this type of filter, I do not think it is a required element. In the “there’s no free lunch” department, apodising filters tend to reduce pre ringing but increase post ringing. To introduce it in the SSP-800 design would require that we re-visit all the other elements in the design to optimize the performance of the system with this different filter. We don’t have any plans to do that.
post #1549 of 5778
And here is another quote from Tom at Classe on apodising filters, which pretty much echos what Dave told Sikoniko.

Quote:


Pre and post ringing of digital filters have been an area of fascination for us for many years and we fully understand the capacity of apodizing filters to reduce pre-ringing. However, they can increase post ringing and add additional processing that we prefer to minimize.

Each element in the signal path must work with the others as a system, so changing one element (like the digital filter) would logically require a re-design of the rest of the signal path. When done right, the whole is greater than the sum of its parts. The SSP-800 is a fine example of this philosophy and delivers what is widely considered ultimate performance with negligible pre and post ringing.

Therefore, we have no plans to incorporate apodizing filters in our designs, but you should have no concerns regarding their absence.

Best wishes

Tom
post #1550 of 5778
Quote:
Originally Posted by sikoniko View Post

Not to rain on anyones parade, but I heard back from Dave and the short answer on apodising filters is that they had considered it at one point but have decided that they can do better without it.

Thanks for getting their position on this. Not sure there's anything in what Dave said that can be interpreted as doing anything better without it, but maybe you meant they are better off as it would require the devotion of significant resources to revisit other design aspects of the SSP for an uncertain gain in performance.
post #1551 of 5778
Quote:
Originally Posted by Roger Dressler View Post

Thanks for getting their position on this. Not sure there's anything in what Dave said that can be interpreted as doing anything better without it, but maybe you meant they are better off as it would require the devotion of significant resources to revisit other design aspects of the SSP for an uncertain gain in performance.

My understanding is that Calsse feels that apodising filters are not the Holey Grail of digital filters. They come with their own set of trade-offs. I also get the impression that they feel that they have minimized the filter ringing to a negligable level in their current design.
post #1552 of 5778
Quote:
Originally Posted by hifisponge View Post

My understanding is that Calsse feels that apodising filters are not the Holey Grail of digital filters. They come with their own set of trade-offs. I also get the impression that they feel that they have minimized the filter ringing to a negligable level in their current design.

To expand on this I think they feel that there is more than one way to skin a cat and they can acheive as good or better results using other methods.
post #1553 of 5778
Quote:
Originally Posted by sikoniko View Post

To expand on this I think they feel that there is more than one way to skin a cat and they can acheive as good or better results using other methods.

So Dave's response contained more information than you first reported? Could you post his entire response?
post #1554 of 5778
Quote:
Originally Posted by Roger Dressler View Post

So Dave's response contained more information than you first reported? Could you post his entire response?

It's not a lot more, but read the response I posted from Tom in post #1549.
post #1555 of 5778
Quote:
Originally Posted by hifisponge View Post

My understanding is that Classe feels that apodising filters are not the Holey Grail of digital filters. They come with their own set of trade-offs.

I'm curious about how they came to the conclusion that there's insufficient merit in using them. I'm not saying their conclusion is wrong--I have no way to prove that. Was it based on actual listening experience, papers, measurements, other?

Quote:


I also get the impression that they feel that they have minimized the filter ringing to a negligable level in their current design.

I think Classe has done a superb job with their DACs--and the entire SSP (bugs notwithstanding ). I take no issue with their sonic achievement.

Minimizing ringing in a DAC is different than removing (pre-)ringing from the source. Since the SSP DACs are always running at "2x" (88.2/96 kHz), and are 8x oversampling, there's no audible ringing issue left to deal with in the SSP other than that of "1x" sampled sources, 44.1/48 kHz. Upsampling them doesn't remove the ringing caused by the original antialias filter. Passing the audio thru a "perfect" DAC doesn't either. This is what the apodising filter uniquely does.

As for the pre- vs post-ringing tradeoff, natural sounds do not pre-ring. And seldom, if ever, do sounds stop as fast as they start, and they exist in reverberant spaces. Post-ringing is therefore likely to be masked, and therefore much less innocuous.
post #1556 of 5778
Quote:
Originally Posted by Roger Dressler View Post

I'm curious about how they came to the conclusion that there's insufficient merit in using them. I'm not saying their conclusion is wrong--I have no way to prove that. Was it based on actual listening experience, papers, measurements, other?

I think Classe has done a superb job with their DACs--and the entire SSP (bugs notwithstanding ). I take no issue with their sonic achievement.

Minimizing ringing in a DAC is different than removing (pre-)ringing from the source. Since the SSP DACs are always running at "2x" (88.2/96 kHz), and are 8x oversampling, there's no audible ringing issue left to deal with in the SSP other than that of "1x" sampled sources, 44.1/48 kHz. Upsampling them doesn't remove the ringing caused by the original antialias filter. Passing the audio thru a "perfect" DAC doesn't either. This is what the apodising filter uniquely does.

As for the pre- vs post-ringing tradeoff, natural sounds do not pre-ring. And seldom, if ever, do sounds stop as fast as they start, and they exist in reverberant spaces. Post-ringing is therefore likely to be masked, and therefore much less innocuous.

That all makes perfect sense. Seems to me you need to write a piece of feedback / make a request directly to Classe.
post #1557 of 5778
Quote:
Originally Posted by hifisponge View Post

That all makes perfect sense. Seems to me you need to write a piece of feedback / make a request directly to Classe. Tom McConville

You mean they don't read the Forum? What are they doing anyway--working??

Yes, I may bring this up with Dave. I'm trying to be gentle on making suggestions for new features (other than the sub crossover idea) until they are more bug-free on the current release. Don't want to distract them.

And to be fair, rather than yammering on about it, I think you've hit the nail on the head--we need some way to better evaluate apodising to see if it would really do anything worthwhile. The anecdotal reports are only so useful--mine included. I liked what I heard, but there was no A/B. That's why I was wondering how Classe came to their conclusion. It's no easy thing to determine empirically.
post #1558 of 5778
Tim,

If I may: It's been reported on AVS that when you place a personal email address like you have in the thread of Mr. McConville, they are prone to receive enormous amounts of spam mail. No personal experience on this topic, but just what I've read in some of the threads.
post #1559 of 5778
Quote:
Originally Posted by Mozvz View Post

Tim,

If I may: It's been reported on AVS that when you place a personal email address like you have in the thread of Mr. McConville, they are prone to receive enormous amounts of spam mail. No personal experience on this topic, but just what I've read in some of the threads.

Thanks Moz. I'll remove it.

Roger, would you also take it out of your quote?

Thanks.
post #1560 of 5778
Quote:
Originally Posted by Roger Dressler View Post

So Dave's response contained more information than you first reported? Could you post his entire response?

I'm very careful in what information I hand down from Dave, and even more careful about what I quote, because I don't like how some people tend to twist what he says. I am somewhat concerned that he could stop the line of communication. Here is the rest of what he said in the context of a follow-up email:

Quote:


we see the trade off generally as not being worth it. So even with a ground-up new design, we aren't inclined to use an apodising filter. You might be able to make a good sounding DAC using that type of filter, but our guys think they can get a better overall result without it.

I think I reflected that opinion in my original response.

anyways, in response to your earlier question, I don't think they read AVS, but I know they read HTGuide. They are aware of AVS, but I think (not something they have directly said) that AVS is high-school drama. They are very proud of having a board over on HTGuide, even though they don't directly participate. They want their customers to feel free to speak their mind and have their own opinions, free of their interjections.
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