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  1. #11
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    Quote Originally Posted by Archimago View Post
    Interesting history there Arny... I assume the effect must have been transparent.
    Listening tests of this device were among our early adventures with ABX:


    http://djcarlst.provide.net/abx_digi.htm

    "The Ampex 16 Bit Digital Delay Line vs. wire comparison was made in a professional recording studio control room on time aligned UREI 813 speakers with McIntosh MC-2100 amplifiers. The audio source was local country artist P. J. Coombes who had been recorded on a 24-track Ampex MM-1000. That tape had been mixed to a 2-track tape at 15 IPS on a Scully 280. The mixdown and playback was through an API console. Thus the master tape played for these ABX trials was of quality not available to the record buyer of the era.

    The listeners included professional recording engineers with years of experience on major label projects, professional maintenance engineers, and recording engineering students.


    For those not familiar with studio equipment, these are some of the most revered pieces of equipment of that day. API consoles are still prized today for their high quality. The studio microphone locker included Neumann U-67,Neumann, U-87, and Neumann KM-86 along with various microphones that might be selected for specific applications such as inside the drums.
    "


    Also I presume there's an AD/DA in the device.
    For sure. It was said to be a proper 16 bit device. Its clock rate may have been adjustable in the 40-50 KHz range. The dB article that I referenced seems to be the sole surviving piece of doc that is stored in public.

    It was tested quite exhaustively, and found to be sonically transparent. Those tests is the origin of my interest in testing gear with a set of keys, jangling. This is quite demanding, and just about everything in a good studio in those days would fail to be transparent enough to pass ABX tests.

    http://djcarlst.provide.net/abx_tapg.htm

    What kind of conversion quality are we looking at with the ADD-1 back in the day for these LP's!?
    I don't have a sample to test, but from analysis of LPs that appear to be cut using it, I would speculate somewhat informedly that it used analog filters, and R2R conversion. The analog filters were relatively gentle by modern standards. The transistion band appears to be huge. A fair amount of loss in the 17-22 KHz range.

    I'm sure Michael Fremer would have no trouble identifying these digitally compro[quotemised LPs .
    :-)

    I'd guess that a very high proportion of LPs that were cut from 1979 to 1989 were cut using it. IOW, during production they were digitized @ 16 bits, and were brick wall filtered at 24 Khz or thereabout. I don't beieve that he has complained about even one instance of this.

    For example, every legacy copy of the DSOTM LP probably received this treatment.

    During loud passages, the brick wall and rejection band is covered up by the nonlinear distortion that is inherent in the LP format:

    Name:  Needle drop of supertramp give a little bit  loud passage.jpg
Views: 436
Size:  182.6 KB

    This is an interesting finding to me, because it turns all of those LPs into potential test records for evaluating the nonlinear distortion inherent in the LP. If analysis of a quiet passage or leadin groove shows the indicated digial artifacts or something like them, then anything above the observed transistion band has to be generated by the LP format itself, as no such signal was ever sent to the cutter head. LPs cut in Y2K and later seem to be free of this issue - the delay may not have been used, or it was running at a higher sample rate such as 24/96.

    To clairfy, the needle drop shown is of a contemporateous Supertramp LP.
    Last edited by arnyk; 2018-01-07 at 05:58.

  2. #12
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    I wouldn't buy anything from HDTracks without researching it first. I buy a lot more downloads from eClassical or Presto, at least 16/44 FLAC. I do like to get the "studio master" versions if it's not too much more expensive than 16/44, what the hell, but I don't bother with 44/24 or 48/24 versions.

  3. #13
    Senior Member Archimago's Avatar
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    Thank you Arny!

    Quote Originally Posted by arnyk View Post
    Listening tests of this device were among our early adventures with ABX:


    http://djcarlst.provide.net/abx_digi.htm

    "The Ampex 16 Bit Digital Delay Line vs. wire comparison was made in a professional recording studio control room on time aligned UREI 813 speakers with McIntosh MC-2100 amplifiers. The audio source was local country artist P. J. Coombes who had been recorded on a 24-track Ampex MM-1000. That tape had been mixed to a 2-track tape at 15 IPS on a Scully 280. The mixdown and playback was through an API console. Thus the master tape played for these ABX trials was of quality not available to the record buyer of the era.

    The listeners included professional recording engineers with years of experience on major label projects, professional maintenance engineers, and recording engineering students.


    For those not familiar with studio equipment, these are some of the most revered pieces of equipment of that day. API consoles are still prized today for their high quality. The studio microphone locker included Neumann U-67,Neumann, U-87, and Neumann KM-86 along with various microphones that might be selected for specific applications such as inside the drums.
    "




    For sure. It was said to be a proper 16 bit device. Its clock rate may have been adjustable in the 40-50 KHz range. The dB article that I referenced seems to be the sole surviving piece of doc that is stored in public.

    It was tested quite exhaustively, and found to be sonically transparent. Those tests is the origin of my interest in testing gear with a set of keys, jangling. This is quite demanding, and just about everything in a good studio in those days would fail to be transparent enough to pass ABX tests.

    http://djcarlst.provide.net/abx_tapg.htm



    I don't have a sample to test, but from analysis of LPs that appear to be cut using it, I would speculate somewhat informedly that it used analog filters, and R2R conversion. The analog filters were relatively gentle by modern standards. The transistion band appears to be huge. A fair amount of loss in the 17-22 KHz range.



    :-)

    I'd guess that a very high proportion of LPs that were cut from 1979 to 1989 were cut using it. IOW, during production they were digitized @ 16 bits, and were brick wall filtered at 24 Khz or thereabout. I don't beieve that he has complained about even one instance of this.

    For example, every legacy copy of the DSOTM LP probably received this treatment.

    During loud passages, the brick wall and rejection band is covered up by the nonlinear distortion that is inherent in the LP format:

    Name:  Needle drop of supertramp give a little bit  loud passage.jpg
Views: 436
Size:  182.6 KB

    This is an interesting finding to me, because it turns all of those LPs into potential test records for evaluating the nonlinear distortion inherent in the LP. If analysis of a quiet passage or leadin groove shows the indicated digial artifacts or something like them, then anything above the observed transistion band has to be generated by the LP format itself, as no such signal was ever sent to the cutter head. LPs cut in Y2K and later seem to be free of this issue - the delay may not have been used, or it was running at a higher sample rate such as 24/96.

    To clairfy, the needle drop shown is of a contemporateous Supertramp LP.
    Wow Arny! Appreciate your comments and demonstration. Great stuff and a wonderful reminder of the transparency from digital even from the old days before all the iterations and focus on home digital audio after the release of CD.

    Beyond all the angst these days about using digital to cut vinyl, this is a reminder of just how far back digital has impacted vinyl production... Something the analogue purists need to keep in mind especially if they cite albums like Supertramp and DSOTM :-).

    I'll have to remember to point to this post in the blog sometime!
    Archimago's Musings: (archimago.blogspot.com) A 'more objective' audiophile blog.

  4. #14
    My experience is it depends on the original master recording and the competency of the remastering engineer.

    I've suffered through some 'high-res' releases that sounded worse than the 25 year old Redbook pressing of it.

    This can be even more pronounced with older masters where no care is taken. I think there is a rush to fleece sometimes with the 24-bit lure.

    I still favor a top vinyl copy over even a fair 24-bit transfer.

  5. #15
    Senior Member pablolie's Avatar
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    Quote Originally Posted by ralphpnj View Post
    CD quality but with a much larger file.
    Awesome summary. :-)
    ...pablo
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  6. #16
    Senior Member pablolie's Avatar
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    Thanks for an interesting read...

    ...I had no idea that digital recording pollution had started as early!

    I present the following little experiment I have gone for over the years with one of my favorite recordings ever.

    Name:  bevans.jpg
Views: 217
Size:  13.9 KB

    One version is a 320k CBR rip from the original CD, the second the HDtracks download, supposedly from the "previously undiscovered, cryogentically-frozen and kept-in-a-vacuum master tape". F__k me if I can ever hear a difference. And I've listened to it on $4k headphones (not mine), spending an utterly unenjoyable hour trying to convince myself I *had* to hear a difference. I've done the same experiment, only comparing a 16/44 and a 24/192 of very well recorded, 2000-ish albums, much to the same result. Maybe *there* I'd be able to detect a difference between the 320 and 16/44 version, but it's not one I'd particularly care for other than for archiving purposes. And I supposedly can still hear up to 17kHz, so it's not like I have deafened myself over the years.

    And now that it's easy to score $2 CDs in the used market, I've rediscovered the joy of roaming around in a music store on a weekend. Vintage CD stores, who would've thought! :-D
    ...pablo
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  7. #17
    Senior Member Archimago's Avatar
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    Quote Originally Posted by pablolie View Post
    ...I had no idea that digital recording pollution had started as early!

    I present the following little experiment I have gone for over the years with one of my favorite recordings ever.

    Name:  bevans.jpg
Views: 217
Size:  13.9 KB

    One version is a 320k CBR rip from the original CD, the second the HDtracks download, supposedly from the "previously undiscovered, cryogentically-frozen and kept-in-a-vacuum master tape". F__k me if I can ever hear a difference. And I've listened to it on $4k headphones (not mine), spending an utterly unenjoyable hour trying to convince myself I *had* to hear a difference. I've done the same experiment, only comparing a 16/44 and a 24/192 of very well recorded, 2000-ish albums, much to the same result. Maybe *there* I'd be able to detect a difference between the 320 and 16/44 version, but it's not one I'd particularly care for other than for archiving purposes. And I supposedly can still hear up to 17kHz, so it's not like I have deafened myself over the years.

    And now that it's easy to score $2 CDs in the used market, I've rediscovered the joy of roaming around in a music store on a weekend. Vintage CD stores, who would've thought! :-D
    Oh no... Say it ain't so!!! Yet another "audiophile" who can't hear the difference between MP3 and lossless! Even though your audiophile membership has been revoked, it's good to hear your honesty .

    I guess as long as the public still pays money for the so-called "hi-res version", it'll be made available no matter the provenance; including all those ancient recordings with no real hope of achieving any benefit from a high-res transfer. Despite the brave face and ongoing showing at CES 2018 from the "High Resolution Audio" supporters, clearly the mainstream isn't biting this year with essentially no coverage except for the special interest groups (those places that still think MQA is somehow a good idea!).

    The Industry seriously needs to wake up. Even if ultimately 99.7564% of listeners would not be able to tell a difference, at least if they're going to sell hi-res recordings, let it be genuine product...
    Archimago's Musings: (archimago.blogspot.com) A 'more objective' audiophile blog.

  8. #18
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    I agree hdtracks is a minefield, and their sampler tracks are a spectacular own-goal. DOYR.

    I buy a lot of newer music. Often that's originally recorded at 24/44, 24/88, 24/96. Occasionally these original numbers are available for download and I buy them (usually from Qobuz or 7digital). In these cases I see down-sampling to 16/44 as an additional step I don't need. It might not be audibly better but hey, it's measurably better. (On a similar note, why should I insert an extra line stage when I don't need it, no matter how transparent it is? That would be bloody-minded IMO. If I need it, fine, but if I don't?)

    Most of the time it's only available in 16/44 - that's fine.

    IMV it depends.
    - Some DACs have sub-par up-sampling (can be fixed with source up-sampling). But some DACs have good digital filtering and can up-sample well themselves. So 16/44 could sound worse than hi-rez when the playback system is not up-sampling well.
    - Some 16/44 had dodgy anti-aliasing filter applied, in these cases the equivalent hi-rez could sound better.

    All that said, I believe if you have access to good up-sampling and a well-made 16/44 recording then there's probably nothing audible. So I'm relaxed generally about 16/44 which, please note, is most of what I have.
    Last edited by darrenyeats; 2018-01-21 at 05:09.
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  9. #19
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    To drop more into the fire, a lot of new artists - those who self record and produce at home, especially their first works - usually deliver 320k MP3s to their labels for digital distribution. Certainly the common case for electronic / dance music.

  10. #20
    Senior Member Mnyb's Avatar
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    You could also add the fact that some analog tapes did not age well .
    The digital copy from 1989 may be as good as it ever gets.

    Also some early CDĺs was simply cut from the LP master tape . A good engineer knows that an LP is not transparent and have some well known issues to workaround so they tweaked it to get a good LP experience.
    The tonal balance etc may sound a bit wrong directly on a transparent media as a CD how about a tad flat and thin

    These two can ofcourse be combined so that the only viable source for the remaster is the CD then you may fix some stuff but your limited .

    Best case they went back to well preserved multitrack sources and redid the whole mixing process from scratch , thats better if we get that treat on in a while.
    But even then the intrinsic sq off every track is still limited but you can use a modern DAW software and have no further detoriation from there .
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