SACD Technology

From Edison cylinders to pre-amps to ProTools: talk about it here.
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krabapple
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Postby krabapple » Fri Feb 24, 2006 10:48 am

Andreas wrote:
Crummy Old Label Avatar wrote:I think the real question is: why does Mr. Perfect Purist have any clipped samples at all on his vaunted disc?

Good question. However, I always assumed you come from the objectivist side of audio discussion. Have you done any AB-test to determine if you can detect 257 clipped samples in a blind test? :)


I don't know, but I do know that I can detect the difference in levels. I levelmatched the two files (CD rip and the SACD A-D transfer that thomh did), using the replaygain values as a guide. Replaygain indicated that reducing the CD version by 1.54 dB would give a perceptually levelmatched comparison. (This accords pretty well with the difference in avg RMS for the two tracks after *peak*-matching.) Then I ABX'd the files using foobar 2k's ABX tool. I got 10/18 correct: no better than chance. Then I performed the same test but didn't levelmatch the tracks. I got 18/18. So *if* the CD version is truly being output at a dB or more greater than the SACD version, people may well hear a 'difference'. But it sure as hell isn't due to DSD vs CD.

I'm going to make .flacs of these available , so people can fool around with them themselves.

Btw, I'm curious to know, is Fortunate Son the loudest track on other versions of this album?
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Postby Crummy Old Label Avatar » Sat Feb 25, 2006 2:24 am

Andreas wrote:However, I always assumed you come from the objectivist side of audio discussion. Have you done any AB-test to determine if you can detect 257 clipped samples in a blind test? :)


I do indeed come from the objectivist side of the discussion.

No, I've never conducted an ABX test to determine clipped samples, but I'd be more than happy to do so. I guess I would have to create a clipped file myself -- unless someone already has clipped and unclipped examples of an otherwise identical sound file. In the name of objectivity, I'd even be willing to listen to CCR. If that's not a magnanimous sacrifice on my behalf, I don't know what is.

I would guess that 257 clipped samples would be difficult or impossible to audibly detect, but I do find it curious that since clipped samples and compression are such a fixation at SHtv, it is rich to find them on one of Hoffman's very own.

Of course, that's undoubtedly the least of it, as SH has been proved to be a liar with his SACD vs. CD nonsense. That won't convince the faithful, of course, but, well, it's good for a laugh, at the very least.
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Postby Andreas » Sat Feb 25, 2006 8:14 am

I would prefer to keep this about SACD versus CD instead of sh.tv versus SC, but to each his own.

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Postby Ess Ay Cee Dee » Sat Feb 25, 2006 5:22 pm

Andreas wrote:I would prefer to keep this about SACD versus CD instead of sh.tv versus SC, but to each his own.


How is this "sh.tv versus SC?" SC has been its own entity since it "spun off" from here last year. Despite what you may be reading into this, I don't think this is simply some anti-SH diatribe.

Do you really think all of SC folks are that obsessed with SHtv? Give us a little bit of credit.

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Postby Andreas » Sun Feb 26, 2006 2:24 am

David's posts about the "257 clipped samples" on sh.tv were not censored, but also not commented so far.

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Postby thomh » Sun Feb 26, 2006 5:40 am

Andreas wrote:About those clipped samples...they don't look "severely" clipped. More like AF Minute By Minute and DCC Eagles Greatest Hits, both of which have clipped samples.


When I look at the rest of the songs and compare my SACD A-D transfers to the CD rip, the numbers all match up except for Fortunate Son which got this 1.5dB difference. Why is that? If you check this file http://home.online.no/~thomh/FortunateSon.xls you'll see that the SACD A-D transfer and the CD rip of the DCC gold match up.

And no, the samples are not severely clipped. However, IMO the original signal has been altered enough to make a fair comparison of subtle echo trails between SACD and CD layer impossible and we must look elsewhere. Somebody should bring that fact to the attention of Mr. Hoffman. Andreas?

Andreas wrote:David's posts about the "257 clipped samples" on sh.tv were not censored, but also not commented so far.


Could you provide a link?
Thom


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Postby Andreas » Sun Feb 26, 2006 5:49 am

thomh wrote:Somebody should bring that fact to the attention of Mr. Hoffman. Andreas?

The problem is that all this research has not been done by me. I don't even have an SACD player (shock!). I prefer to post things that I either observed by myself, or that I can confirm by myself.

Of course, I could confirm that there appear to be clipped samples on the redbook layer (and some DCC Gold CDs and AF Minute By Minute)...but that's not the point.

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Postby thomh » Sun Feb 26, 2006 5:54 am

Andreas wrote:http://www.stevehoffman.tv/forums/showthread.php?p=1612323#post1612323
http://www.stevehoffman.tv/forums/showt ... ost1611310


There is too much noise in that thread so I would suggest starting a new one.
Thom

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Postby thomh » Mon Feb 27, 2006 11:29 am

Andreas wrote:The problem is that all this research has not been done by me. I don't even have an SACD player (shock!). I prefer to post things that I either observed by myself, or that I can confirm by myself.


Fair enough. Check your PM.

Andreas wrote:Of course, I could confirm that there appear to be clipped samples on the redbook layer (and some DCC Gold CDs and AF Minute By Minute)...but that's not the point.


Are you saying that mastering differences, whether accidental or otherwise, between the two layers is not a factor when trying to determine subtle differences between SACD and CD? I would think a level playing field would be of prime importance.
Thom

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krabapple
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Postby krabapple » Mon Feb 27, 2006 9:07 pm

thomh wrote:
Andreas wrote:http://www.stevehoffman.tv/forums/showthread.php?p=1612323#post1612323
http://www.stevehoffman.tv/forums/showt ... ost1611310


There is too much noise in that thread so I would suggest starting a new one.


what are the titles of those threads? Clicking URLs doesn't work for us banned/suspeded folk.
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Postby lukpac » Mon Feb 27, 2006 9:18 pm

Copy and paste vs. clicking the links.
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