Revolutions Per Minute

    The DMM Dubplate, Vol. 1 and the Art of Pushing the Boundaries, Part Three

    Issue 149

    Part One and Part Two of this series were published in Issue 147 and Issue 148.

    Was DMM (direct metal mastering) ever intended to offer a sonic improvement, compared to “prior art"? When it comes to normal mass-produced vinyl records, it is hard to tell. Whether lacquer or DMM, the majority of records out there were never mastered (or even recorded) with absolute sound quality in mind. The development of disk mastering (and recording technology) reflected the general mood in the industry. Quantity over quality. More output for your investment. Professional recording equipment and disk mastering systems were being developed to allow less-skilled personnel to get the job done, faster. Not necessarily better, but faster. This is not to say that the equipment could not produce high-quality results. But this was neither the major selling point, nor its most popular application.

    Which is why it is hard to really compare between DMM and lacquer strictly in terms of sound quality. Most of what we may not like in a record is more often than not a result of substandard recordings, mastering done in haste, inadequate quality control, or, all too often, desperate attempts to fix a not-so-good performance, to at least have a product to sell. It is extremely rare that we would really get to hear the actual full benefits of the technology. It is the human factor that overwhelmingly tends to underutilize the available technology, producing results that fall short of expectations and potential. Which is why properly made records can and do sound so impressive, when we come across them.

    Both DMM and lacquer mastering have produced outstanding products, as has tape and even (I am clearly biased in favor of analog audio technology, but credit is due where credit is due) properly implemented digital technology.

    It has been widely discussed, mostly in speculation, that DMM sounds harsh due to the use of a 30 kHz tone fed to the cutter head to assist with cutting the copper surface of the disk.

    This is only partially true. In the very early days of DMM, the blanks were not very refined. The copper layer was quite hard, and to achieve the desired surface finish in the cutting operation, a 30 kHz tone was used to vibrate the cutting tool (stylus). This may seem like a bit of a crude afterthought, and for audio purposes, it probably was, but rather impressively, considering that this was the early 1980s, it was one of the first (if not the first) practical implementations of ultrasonic vibration-assisted machining, which is currently all the rage in the precision engineering and nanotechnology sectors.

    This innovation was short-lived in disk mastering (fortunately for those with sensitive hearing), as Teldec promptly improved their blanks, using the softer copper phosphate layer that is still in use to the present day. So, with the improved blanks, the required surface finish of the groove could be achieved without having to resort to technologies that would be more appropriate in dental laboratories. The 30 kHz tone was turned off, and has remained off ever since. Günter Pauler has personally confirmed in private correspondence that they do not use the 30 kHz tone on their Neumann VMS-82 DMM lathes, at Pauler Acoustics/Stockfisch Records.

     

    DMM Dubplate, Vol. 1.

    DMM Dubplate, Vol. 1.

     

    Other authors, perhaps less familiar with the historical developments in disk mastering technology and industrial manufacturing, have speculated that the 30 kHz ultrasounds they can hear (!!!) or measure (more likely) on their DMM-mastered records must be a result of the cutting stylus "chattering" (uncontrollably vibrating as a result of the forces of the cutting operation). While this can occur, it is by no means a normal operating condition, neither on master disks, nor on machine tools of other kinds. I have personally measured all the DMM-mastered records in my collection for the presence of ultrasonic tones (30 kHz or otherwise) and have never detected any. I guess I do not own any of the early DMM records, which still used the old type of blank disk and the 30 kHz tone.

    Having clarified and verified that the Stockfisch DMM Dubplate Vol. 1 does not contain any 30 kHz tones, we shall proceed to examine other important parameters. For instance, does it contain secret messages when played backwards? Nah, just kidding.

    As with all masters, they can only ever be as good as the source they are created from. Somewhat surprisingly, the recordings contained in DMM Dubplate, Vol.1 all started life as 44.1 kHz/16 bit (CD-quality) digital recordings. Even nowadays, Stockfisch Records use a sampling rate of 44.1 kHz but at 24 bits, firmly believing it to be superior to higher sampling rates. This is based on a series of papers published by Dan Lavry, a manufacturer of popular converters in the professional recording and mastering world. Since then, many more recent papers have been published by leading authorities in digital audio and signal processing which challenge this point, concluding that there are significant advantages to using higher sampling rates.

    DMM Dubplate, Vol. 1 disc.

    My own scientific measurements can only confirm the technical advantages of the higher sampling rates, especially in the time domain, which often gets overlooked. However, Stockfisch Records are so confident about their preference of the 44.1 kHz sampling rate that they have even released a comparison test on USB stick, called "Trust Your Ears" (SFR 357.3003.0, 2017), offering direct comparisons between 44,1 kHz/16-bit, 96 kHz/24-bit, 192 kHz/24-bit, 2.8 MHz DSD, and 5.6 MHz DSD, each recorded natively from the same sources, a mechanical 16-inch cylinder music box and an analog magnetic tape. This will be reviewed in detail in a future issue.

    Putting the needle down on DMM Dubplate, Vol. 1 for the first time, I was greeted with silence. I mean, serious silence. Which I sort of expected, being accustomed to playing back masters and mothers. These really demonstrate the true dynamic range potential of the medium, in a practically achievable setting, using existing playback technology. The grooves of DMM Dubplate, Vol. 1 are extremely silent, on par with any well-made master disk. A few seconds after the silence, the music begins almost unexpectedly, with pristine clarity and detail.

    The transition from the most silent parts to the musical peaks is effortless and impressive. It is as silent as a master disk, but with the detail, dynamics and clarity of a metal mother. After all, the DMM Dubplate is at the same time both a master disk and a mother. It offers a truly intense listening experience, and all this from CD-quality source material!

    Which brings us back to my point stated at the beginning of this piece: that it is indeed rare in audio for the technology to be used to its fullest potential. When it does, the results can be way beyond expectations. Undeniably, the tracks contained within DMM Dubplate, Vol. 1 are some of the finest 44.1 kHz/16-bit recordings ever made, transferred to DMM disk in what I would describe as the most elegant transfer possible.

    Header image: Inés Breuer, Hendrik Pauler, Hans-Jörg Maucksch and Günter Pauler of Stockfisch Records.

    2 comments on “The DMM Dubplate, Vol. 1 and the Art of Pushing the Boundaries, Part Three”

    1. Stockfisch issued a DMM Cut Vinyl Series 180 gram LP, (SFR 357.8006.1) and a DMM-CD/SACD VOL. 1 (SFR 357.5900.2) that have, in common with the DMM Dubplate, Vol. 1, the same first track, Chris Jones NO SANCTUARY HERE. I own the first two, but not the third.
      Comparing the LP issue with the Dubplate, how many more generations are used to make the LP?
      And, have you compared the sonic attributes of the vinyl LP and/or the CD/SACD against the Dubplate?
      Personally, I now have comparisons of my own to make: CD layer vs. SACD, and the winner against the LP.
      Admittedly, comparing a CD against vinyl is complicated by having 2 different playback chains. This may be an issue for one to solve within the context of one's own system.
      Interesting that they record at such low bit rate! I'm grateful that you included that info in your commentary. But for you, I would might never have heard of the Dubplate.

    2. according to Burkhard Vogel / "The Sound of Silence", p 140, the first generation of DMM heads (or amps?) did not use ultrasonic frequencies. he writes "To further reduce the noise of the vinyl record in the 80-ies of last century Teldec improved its DMM process by adding a 80 kHz signal that overlays the signals in B20 k. It is said hat this process should have improved the records surface by “polishing” it with that high frequency tone, thus, reducing significantly the noise level as well."

      the 80 kHz (vs. Pauler's 30 kHz) makes sense because the frequency is far enough above not only the audio band, but also the typical resonance peaks of MC cartridges. also, 80 kHz correspond more with the intended smoothing of the copper surface with the cutting stylus. the stylus excursions at that frequency will be minute enough so as not to frequency modulate the music signal. (add to this the mysterious "Neumann constant" around 50 kHz that was rumored to prevent the RIAA-emphasized high frequencies from extending to daylight of infinity, whatever you prefer. as far as i know, this "Neumann constant" never existed – it was first mentioned by Allen Wright in his book published in the mid-1990s. i believe it was plain simple a function of loop gain in an NFB circuit.)

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