A New Audiophile Term: “Micro Reflections”

I got a call yesterday from the same guy that spent so much time with me here at the studio investigating high-resolution audio. He’s spent weeks learning about high-resolution audio so that he can digest things into an article that will be completed soon and distributed widely. He had a couple of additional questions for me after speaking to all of the major players in this new recording initiative. He’s spoken to hardware people, digital music download sites, the major labels, Pono, and the developers of MQA. I’m impressed that he’s doing such a thorough job. And I was particularly thankful that he contacted me once again near the end of his research.

As you might expect, he left our initial meeting knowing about provenance and the campaign of misinformation being perpetuated by the major labels, official organizations, and rock icons. His follow up call was necessary because there was a lot of push back from those parties. The author was armed with a good understanding of the recording process and the conversion of analog tape into PCM digital words. He managed to fend off the silly arguments about how PCM digital is a set of “stair steps” but heard from a major label guy about how analog tape transfers to high-resolution PCM digital bit buckets are capable of capturing the “micro reflections” in the original audio source.

I have to admit that this is a new one for me. I’ve heard about “low level details”, “micro dynamics” and “analog resolution” but hadn’t encountered “micro reflections” previously. So I looked it up. A Google search turned up a $132.99 book titled “Digital Audio Broadcasting: Principles and Applications of DAB, DAB + and DMB”. The quote from page 286 applied to signal reflections found in transmission systems…and not in high-end audio reproduction. Not relevant.

The idea of “micro reflections” was brought up in defense of high-resolution audio files made from analog tape. I wasn’t part of the conversation and lack context but it was suggested that transfers of older analog tapes to high-resolution PCM files are better able to maintain the “micro reflections” found in the original performance and captured on analog tape. I guess that means that a CD capture of the same analog tape wouldn’t contain the same “micro reflections”. What is going on here?

First generation analog tape can deliver about 12-bits worth of dynamic range…around 72 dB at the most. That’s means below that level the hiss and noise inherent in the tape rises above the desired signal (it gets worse after several generations…vinyl LPs are generally from third generation tape copies). The “micro reflections” associated with long reverberation tails fall below the noise pretty quickly on analog tape. And since the noise floor of a compact disc is much, much wider than analog tape, it seems reasonable to assume that all of the desirable “micro reflections” are perfectly captured by CDs and well as high-resolution formats.

The amount of nonsense being put forth by advocates for high-resolution audio isn’t necessary or helpful. All audiophiles want to know is how was a recording produced and how did it find its way to the high-resolution digital music download sites. Making up justifications and using terms like “micro reflections” just makes the major labels sound confused and dishonest. They’re not the only ones.

The advocates for high-resolution audio should take a step back and start providing accurate and useful provenance information. Then we can move ahead and build a market.

Dr. AIX

Mark Waldrep, aka Dr. AIX, has been producing and engineering music for over 40 years. He learned electronics as a teenager from his HAM radio father while learning to play the guitar. Mark received the first doctorate in music composition from UCLA in 1986 for a "binaural" electronic music composition. Other advanced degrees include an MS in computer science, an MFA/MA in music, BM in music and a BA in art. As an engineer and producer, Mark has worked on projects for the Rolling Stones, 311, Tool, KISS, Blink 182, Blues Traveler, Britney Spears, the San Francisco Symphony, The Dover Quartet, Willie Nelson, Paul Williams, The Allman Brothers, Bad Company and many more. Dr. Waldrep has been an innovator when it comes to multimedia and music. He created the first enhanced CDs in the 90s, the first DVD-Videos released in the U.S., the first web-connected DVD, the first DVD-Audio title, the first music Blu-ray disc and the first 3D Music Album. Additionally, he launched the first High Definition Music Download site in 2007 called iTrax.com. A frequency speaker at audio events, author of numerous articles, Dr. Waldrep is currently writing a book on the production and reproduction of high-end music called, "High-End Audio: A Practical Guide to Production and Playback". The book should be completed in the fall of 2013.

30 thoughts on “A New Audiophile Term: “Micro Reflections”

  • May 10, 2015 at 12:25 pm
    Permalink

    Digiphobiatitis is a modern disease, commonly associated with high fever, raving, and delusions, and only reaches epidemic proportions in first-world countries. I have come to the conclusion that this is the only way to make rational sense of the irrational, anti-factual nonsense that pours forth from the minds and mouths of the afflicted.

    Time has shown that there are medications that can relieve the afflicted, but to their great misfortune, the condition includes a massive delusion that they are in fact the only rational people left and that they are not unwell and don’t need any medicine. Medications are therefore habitually refused by the afflicted, unfortunately, and offers of medication can be met with paranoid defensive aggression. Only appropriate professionals should consider administering medications.

    The national boards of medicine around the world are monitoring the situation, but at this point in time are not recommending that the afflicted be quarantined indefinitely in straightjackets, but they do advise taking precautions and limiting one’s exposure to the afflicted. It is not contagious of course, any more than you can catch insanity from contact with a madman, but prolonged exposure to the raving delusions of the afflicted can be mentally draining and ultimately can reduce the quality of life for normal, healthy people.

    Reply
    • May 11, 2015 at 9:39 am
      Permalink

      Hmmm…maybe there’s a vaccine, too.

      Reply
  • May 10, 2015 at 12:37 pm
    Permalink

    I find it humorous that the industry has to invent new words to support the sale of HiRez buckets of analog masters.
    But from every thing I read the analog master tapes are rapidly deteriorating and must be archived to some modern format soon before it’s too late. So what we have to ask our self is what would be the most appropriate format.
    Although by the numbers; red book pcm is sufficient I don’t think either of us would advocate using that for histories archiving of our wealth of music. Since in today’s world the bandwidth for 24/192 is so easy to come by I believe that would get my vote just as a margin of safety even if it is a bit of overkill. 24/96 or 24/88 would probably be just as good.

    Reply
    • May 11, 2015 at 9:41 am
      Permalink

      If given the opportunity to do an archive of wonderful analog master, I would use a Studer from ATAE (Fred Thal) into a Benchmark ADC-1 running at 192 kHz/24-bits using DH Labs cables…this is future proof.

      Reply
  • May 10, 2015 at 12:58 pm
    Permalink

    I read your blog regularly. All my computer music goes through a good 2 channel DAC-which limits me to stereo. As more surround downloads arise, I may buy a 5 channel DAC. For now, I rely on a Denon DBP 4010 Blu-ray player for surround. In a recent article you said all DVD players are limited to 24 bit/48000 hz output. Does this also apply to Blu-ray? I am setup to output by either coaxial digital or 6 channel analog. Is one higher definition than the other, or does it come down to the Denon DAC vs the Preamp DAC. I have bought some of AIX’s Blu-ray discs. Am I getting the maximum out of them through the Blu-ray player? Thanks

    Reply
    • May 11, 2015 at 9:42 am
      Permalink

      Blu-ras suffer the same mandated down conversion on the digital outputs…with the exception of HDMI in selected models. If you convert at the player, you’re good. If you send the signal digitally via HDMI to an AVR, you’ll get full res but with poor converters.

      Reply
      • May 11, 2015 at 1:36 pm
        Permalink

        ‘…with the exception of HDMI in selected models.’
        Would be nice wth a list of these ‘exceptions’.
        P.S. We know about the Oppo’s!

        Reply
        • May 11, 2015 at 4:01 pm
          Permalink

          I can only comment on the units I know about. I have some others I can check…

          Reply
  • May 10, 2015 at 1:13 pm
    Permalink

    The “micro reflections” in the original audio source could be a reference to distortion caused by an impedance mismatch in a source recording component such as a microphone cable. If the amplitude of this distortion is high enough, it would be captured in the analog tape recording. The term “micro reflections” could also have been used to refer to the sound reverberation and echos in the original recording space. In either case 44.1/16 PCM should be capable of capturing most of this “micro reflection” distortion, 96/24 PCM might be slightly better.

    Reply
    • May 11, 2015 at 9:43 am
      Permalink

      Thanks…this was a new one to me and sounds like a fabrication. The person who made the comment is not an electrical engineer…

      Reply
  • May 10, 2015 at 1:25 pm
    Permalink

    Mark,
    Are “Micro Reflections” a new term for what we have always been using that silly old term “Early Reflections” for, or are these another acoustical phenomena that I should be studying up on to improve my knowledge, and thus quality of my recordings?

    Thank you,

    John Chase

    Reply
  • May 10, 2015 at 2:12 pm
    Permalink

    One of the talents of the human auditory system is the ability to filter out signals from noise – known as the cocktail party effect.So, it’s entirely possible we can make out some musical content buried beneath the uncorrelated noise at -72 dB. That said, the noise floor of a 16-bit system, being another 20 dB down, would seem to be a sufficient margin.

    The reason for doing the transfer at 24 bits is the same as for doing original recordings at 24 bits: it provides room to do postprocessing without harming the useful part of the signal. Besides, can you even find an ADC that operates at 16 bits anymore?

    As for higher sample rates, analog tapes can, and often do, have frequency content well above 20 kHz, and, in any case, moving the antialiasing filter far outside of the audio band has other benefits. In many posts, you’ve acknowledged these facts. In others, you say that CD spec is sufficient for capturing what’s on the tape.

    Reply
    • May 11, 2015 at 9:47 am
      Permalink

      Andrea, the commercial recordings that are being released don’t use anywhere close to 16-bits of dynamic range. Going to 24-bit is the right thing to do while recording but is completely wasted in reproduction. I believe that CDs can deliver virtually all of the fidelity coming from the analog tapes stored in the vaults of the major labels. If given the opportunity, I would do transfers at high-resolution specs.

      Reply
  • May 10, 2015 at 8:02 pm
    Permalink

    Mark;
    I was listening to a Warner Brothers Records CD this evening and noticed the following on the cover;
    “The music on this Compact Digital Disc was originally recorded on analog equipment. We have attempted to preserve, as closely as possible, the sound of the original recording. Because of its high resolution, however, the Compact Disc can reveal limitations of the source tape.” I think this parallels what you have been saying in your last several posts, and this is coming from the label itself.

    Reply
    • May 11, 2015 at 9:50 am
      Permalink

      Interesting, I haven’t seen that previously.

      Reply
      • May 11, 2015 at 10:48 am
        Permalink

        I think I’m right in saying that message was on almost all early CD’s – although I can only speak for the UK at that time.

        Reply
        • May 13, 2015 at 12:39 pm
          Permalink

          Yes, that short notice about revealing limitations of the analog tape was on all early CDs in the USA as well.

          Reply
  • May 10, 2015 at 8:19 pm
    Permalink

    As you may have already gathered Mark, I’m something of an advocate for the good old CD and the as yet relatively untapped level of information it contains. DAC developments in recent years have demonstrated that all those claims of harshness etc. were in fact a simple technical limitation as DAC technology matured.

    Indeed as I write this, I’m listening to a rip of disc two my 1990ish copy of Frank Sinatra The Reprise Collection box set and it sounds wonderful on my current equipment, exhibiting fidelity that I simply would not have thought possible when I first bought it. Remarkable in every way. If you don’t own this one, try to track it down.

    I 100% share your view that the currently in vogue vinyl is really the wrong answer to achieving higher fidelity and is hugely limited by the technical constraints of committing music to grooved plastic. I also agree that the assertion that old analogue recordings can ever be improved by higher res iterations is a total smoke and mirrors exercise.

    Therefore may I suggest that the time is right for a reassessment of the value of CD in preserving older music at a level of fidelity that cannot currently be surpassed.

    Just as people threw away their vinyl when the digital revolution really started to kick in, I sense that the download culture and rubbishing of CD by some commentators is consigning the silver platters to the bargain bin, effectively grabbing defeat from the jaws of victory at a time when digital hardware development is mining more gold from CD than we ever had any right to expect.

    The promotion of hi-res audio would be more credible, in my view, if it completely focused on more recent recordings that are capable of swimming in the 96/24 waters, and beyond (though that’s arguably OTT).

    Reply
    • May 11, 2015 at 9:51 am
      Permalink

      Chris, if the high-resolution audio catalog only consisted of new recordings made at HRA spec, there wouldn’t be enough content to fill your iPod or A&K device.

      Reply
      • May 11, 2015 at 10:51 am
        Permalink

        Agreed Mark, but it would be a more credible starting point.

        Reply
        • May 11, 2015 at 1:48 pm
          Permalink

          Very true, but then the labels wouldn’t be able to once again cash in on reselling their old catalogs once more. And mark my words once the market for the current 24/196 or DSD downloads have run their coarse, someone will introduce a new format that sounds even more “analog like” and the cycle will begin all over again. It will continue on until most everyone who still cares is dead. 🙂

          Reply
          • May 13, 2015 at 12:42 pm
            Permalink

            Well we already have DXD (352 khz at 32 bit) starting up. And the DSD folks have the built in upgrade. DSD128, DSD256 and how long before DSD512. DXD has the advantage that half the people I see know it is high rate PCM and half think it is some higher rate DSD.

          • May 13, 2015 at 1:02 pm
            Permalink

            I believe DXD is deliberately meant to invoke DSD…in fact, that’s what I thought originally. The two are routinely placed adjacent to each other i.e. DSD/DXD when they couldn’t be more different.

  • May 10, 2015 at 9:27 pm
    Permalink

    Hello Mark,

    Micro-reflections is a new term to me too. It sounds like something the marketing department made up.

    While the noise floor for CD’s is technically lower than that for analog vinyl or tape, there is widespread belief that analog sources just sound better and that the resolution of CD’s has failed to capture that (probably unmeasurable) quality. Why use high-resolution at all if CD resolution (44.1 khz/16 bit) is more than good enough?

    It is my experience that high resolution files sound better than CD’s so it makes sense to me to remaster old analog recordings because, for whatever technical reason, it captures more of their elusive quality.

    Don.

    Reply
    • May 11, 2015 at 9:55 am
      Permalink

      Analog formats may be preferred because of their “sound” but that is a matter of personal taste. CD can be truly wonderful and are capable of capturing virtually all of the fidelity we’ll ever need. But it is possible to do better. Not a lot better but still better. The magic however, is in making recordings that sound better with the best format available. This is where we fail miserably.

      Reply
  • May 12, 2015 at 12:58 am
    Permalink

    Once they exhaust all the micro-thingies they will delve into the nanos and then the picos… Sub-atomic details will be the limit..

    Reply
    • May 12, 2015 at 10:26 am
      Permalink

      That and I’ve heard talk about 3072 kHz sample rates…here we go.

      Reply
      • May 13, 2015 at 12:46 pm
        Permalink

        Well surely on the other end of the scale that will turn into 3 megahertz.

        I wish I still knew where I saw it. But there was some audiophile forum talk a couple years ago about some Japanese label experimenting with very high bit rates. The tale was every increase caused a noticeable improvement in sound quality and got closer to analog tape. The highest they had done was 1536 khz. The spiel was you really didn’t get close until 786 khz.

        Reply
        • May 13, 2015 at 1:03 pm
          Permalink

          Like getting closer to analog tape is a good thing. That would be moving backwards. 96 kHz/24-bits is more than enough.

          Reply

Leave a Reply

Your email address will not be published.

one × four =