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.

23 thoughts on “Get With The Specs…Get The Logo

  • There probably aren’t many recordings that can match these definitions.

    Reply
    • Admin

      It depends…there are between 15,000 – 20,000 transfers from older analog masters (which is where the source and delivery specifications may differ) and there are around 30,000-50,000 recordings that have been done natively at 96/24 or better. This doesn’t mean that they maintain that level of quality…but at least they were recorded at the high-resolution spec.

      Reply
  • lazy

    It does look better. I realize not all battles can be fought, much less won, all at once but it would be great if (ranked in rough order of my opinion of importance):
    1) Something indicated that dynamic range was compressed (thinking back to the DDD/AAD/ADD codes).
    2) “Capability of recording” was replaced with “recorded” or better yet state a maximum recording chain noise level consistent with a very low noise recording environment to robustly define “capability” (or something along those lines that satisfies that intent)
    3) Ensuring music is not distributed or marketed in a format of higher digital resolution than the lowest digital resolution in the production chain (as defined by the worst of the digital equivalent of analog noise levels or actual digital resolution).
    4) Something indicated or was explicitly defined such that a maximum of one A to D or D to A conversion occurred in the recording/mixing/mastering process
    5) Clarification was made that the music was not processed in a digital format upconverted (either in bit depth or sample rate) from the lowest resolution allowed in this spec in the production chain
    6) The “decoding”, “digital signal processing”, and D/A conversion” lines apply to minimum requirements the recording/mixing/mastering chain. If so, that’s all cool and would address #5, but since we’re talking the music industry it is worth clarifying that’s what they meant and were not specifying consumer playback requirements or just the maximum capability (used or ignored) of just one step of the production chain.

    I was trying to come up suggestions to produce the highest quality audio, while preventing the anticipated clever and relentless efforts by major labels and engineers to claim the benefits without truly satisfying the underlying intent.

    The most important element for high quality music (to me anyway) is #1. Currently there is no single robust measurement of dynamic range in a recording that is widely used in the audio industry that is easily available to consumers at the point of purchase. The dynamic range measurement popularized via the TT dynamic range meter and database has been thoroughly debunked as something accurate or meaningful: it’s easy to add or filter out inaudible frequency components to fake a high TT DR rating, and the major labels are likely far more aware of this than me.

    Reply
    • Admin

      I like the refinements that you’ve mentioned.

      Reply
  • Camilo Rodriguez

    Hi Mark,

    I find the chart positive in the sense that it tries to set standards, but how many microphones have a response performanceof 40kHz or above? The only ones I can think of are the Earthworks QTC40/QTC50s and the DPA 4004/4007s. I know that Barry Diament uses the QTC30s and that most the classical labels use DPA 4006s, and that all the Schoeps and Neumanns commonly used don’t meet the 40kHz criteria.

    Would you agree with the 40kHz specification, and, which mics, mic preAmp and AD converter do you use for recording?

    Cheers

    Reply
    • Admin

      You’re right the equipment we’ve been using for decades may be lacking. But I find that all of my recordings contain frequencies above 20 kHz…and I use the standard array of microphones. I have B&Ks, AKG, Neumann, AEA and DPA mics. I run them through Benchmark Preamps into Crystal ADCs.

      Reply
      • Camilo Rodriguez

        Hi Mark,

        Thanks for your response and for sharing about your recording arsenal. I think its high time to do some spectagrams of recordings by labels like Hyperion, BIS, Carpe Diem, DECCA, Channel Classics, Dacapo, Aeon, alpha, CHANDOS, Ramee, 2L, naive, Harmonia Mundi, etc., and also some of the more successful Jazz labels like ECM, ACT music and enja, that sell 24bit downloads via QOBUZ, etc. All these labels are selling lots of 24bit downloads, and I’m not so sure they would all pass the test. It would only be fair to consumers and good for the health of the 24bit download market to see some specs that represent current recording practices.

        Cheers!

        Reply
        • Admin

          I’ve looked at a lot of the labels that you list and generally speaking they do a very good job. The ones using DSD 64 won’t qualify because of the lack of ultrasonics and I’ve caught a couple sample doubling. The fact is that everyone (including me) wants to stay in business by selling as much as they can. If the reviewers are happy then the customers will come. How many reviews have you read from computer audio sites that cheer for albums/tracks that don’t have any HD credentials? It’s just part of the business.

          Reply
          • Camilo Rodriguez

            One thing one could do is do spectagrams as part of reviews, or of albums that have been reviewed and “cheered for”. This would ultimately force the most read reviewers and magazines to start doing their own spectagrams to avoid obvious blunders and misrepresentation.

            When the HRA aspect of an album is highlighted beyond the musical aspect, it should be accurate, and offering a couple of spectagrams on the side would be a good idea. A great incentive for labels that are doing a good job and an even beter one for those that need to step up their game. The same way John Atkinson chimes in to provide his measurements, he should chime in with a couple of spectagrams and give kudos to well done recordings.

            Greetz

          • Admin

            My HRADB site will have spectrograms for all of the tracks.

  • Dimethios

    The only thing that worries me is the wording :

    ‘Capability of recording’ – To me it sounds like they could get away with recording at a lower bit rate and still have it considered Hi-Res, ie a re sampling into that range.

    Reply
    • Admin

      You may have a point…but this is so much better than the DEG and CEA definition.

      Reply
  • Camilo Rodriguez

    And then there’s the reproduction chain! How many DACs and Power Amps out there can you show me that have a bandwith equal to that which was established as minimum for microphones, in order to reproduce HRA recordings with the minimum specs mentioned above?

    If there’s significant audio to be recorded up to a minimum of 40kHz, which microphones, microphone preAmps, A/D converters of the recording chain, and which D/A converters and Pre/Power Ams of the playback chain comply with that? Most gear is made to meet the 20kHz standard.

    As much as this table of MINIMUM specifications for recording standards is a positive signal, in the sense that it clearly sets the bar for HRA above CD specs, it adds up to the pile of limitations of the gear we commonly use to both record and reproduce – and with which some claim or believe to hear the difference between CD and HRA audio – our 24bit downloads and “HRA” material (of which the overwhelming majority have definitely NOT been recorded with mics that meet the 40kHz standard proposed).

    Cheers!

    Reply
    • Admin

      The point is that the hardware companies will have to up their game. They should love that.

      Reply
      • Camilo Rodriguez

        My first thought is exactly the same, they should like the idea of selling all their microphones all over again. On the other side, my guess is that if there aren’t so many mics out there that do 40kHz, it’s because it’s not an easy task to produce them. Look at the selfnoise of the DPA 4004/4007, for example. You get stellar dynamic range and SPL handling, good enough for HRA, but at a price. And, we are only looking at omnidirectional mics.

        Nevertheless, the point I was trying to make, is that the gear that actually supports HRA recording and playback is so limited, we should take a step back and review every piece of the recording and playback chain to see if what is being promoted and sold as HRA really passes the test. In other words, if those uncompressed and minimalistically mastered recordings, like the ones made by MA recordings, Soundkeeper Recordings or AIX records, or those made by larger more commercial labels that do multitrack recordings with considerable mixing and mastering, like Hyperion, BIS, DECCA, Naxos, or ECM, ACT, nonesuch, etc., are actually what they advertise, and if their 24bit downloads are worth the extra cost, if the equipment used isn’t up to the job?

        Cheers!
        Cheers!

        Reply
    • Admin

      Thank…very interesting the differences.

      Reply
  • Jim

    I find it odd that the Sony spec calls for a top frequency of “40KHz or above” in several areas without stating a tolerance. So if my beat up old SM58 has response to 40KHz, but its -50dB down from 1kHz, it qualifies?? I don’t think so. There must be a stated response tollerance, or it’s completely meaningless.

    I also have a problem with the free and off-handed use of “24 bit”, as if that actually means something. So, my cheapo 24 bit sound card that does in fact produce 24 bit audio files, but has a noise floor at -98dBFS qualifies? Again, I don’t think so, that’s a 17 bit ADC with 7 bits of junk. The bit depth is about half the story, if the system dynamic range isn’t actually specified, then it’s just marketing hype.

    There are very few real-world ADCs with real 24 bits of dynamic range. I know of one. That doesn’t mean the others don’t offer 24 bit audio files, but there’s a range of quality that spans almost 48dB! That’s why we need a number put on it.

    It’s quite easy to come up with a total dynamic range figure of the entire system, takes a few seconds, and then becomes meaningful as a spec. Yes, I know no mic in a room comes close to 24 bits, but that’s a totally different noise spectrum than a ADC with 5 or 6 of its LSBs dancing around.

    And those transducer speaker specs…silly. Capability of 40KHz and above? At what level? Response tolerance? Dispersion? Again, so my old speaker actually does go to 45KHz, ok it’s at -40dB, but it does have response up there. Of course, the dispersion is a pencil beam that I don’t actually sit in…see my point? There’s a whole lot of stuff that’s being blown right past. These are all marketing hype statements, not technical requirements or specifications.

    How about…microphone and preamp systems: flat response to at least 40KHz, +/-3dB? How about speaker response flat to 40KHz +/- 5dB, dispersion angle +/- 10 degrees at 40KHz? How about total system dynamic range of 100dBFS, including mic preamp and ADC?

    By the way, do all of that and you do exclude analog tape sources, as it should be.

    Recording and reproducing accurate ultrasonic content is non-trival, challenging, and exactly what HR audio is all about. If we don’t lock in some real engineering – type standards, we’ll just be having this same battle every few years, confuse the buying public, and shoot ourselves in the foot…again.

    Reply
    • Admin

      The JAS spec has to be simple for consumers to understand…and I think it is. The meaning is in the right place but the exact specs are lacking. I’ll try to find out if the JAS has any additional information and whether the adoption of the logo comes with a rigorous testing procedure.

      Reply
  • Alex S

    Hi, Mark!

    You state that the proposal in the table leaves out provenance. Can you explain? I thought the table implied provenance starting with the microphone.

    Kudos to Lazy…the listed clarifications are fantastic.

    Question: Isn’t dynamic range implied by 24 bits? To complete the dynamic range picture, don’t we just specify the microphone and amplifier range in cB?

    Finally the table needs to add a transducer–speaker or headphone– tas the final row in the table!

    Reply
    • Admin

      Simply stating that a piece of equipment meets a particular specification doesn’t mean we know that production path the preceded that gear of follows it. I can purchase an AVR with great specs and play a CD or a piece of vinyl or even a Blu-ray Pure Audio disc. But there’s nothing that informs me about the type of equipment that went into the vinyl LP or Blu-ray disc. The Pure Audio format is perfect example. The demonstration tracks that I have are from older sources…and are limited by the provenance of the great.

      Dynamic range is determined by the word length…yes. But virtually every recording every released uses less than 24-bits on reproduction.

      Reply
  • Alex S

    Hi, Mark!

    Thanks for clarifying. I didn’t think of the process steps not respecting the upstream resolution.

    Don’t you think the effort to create this table is a tacit acknowledgement of your impact on how we should define high resolution audio?

    Reply
    • Admin

      Alex, I would love to think that my writings and involvement in the high-resolution audio space matters but I seriously doubt it. The power brokers are well-funded organizations, the labels, the Recording Academy, and rock stars. I’m an engineer, producer, and educator with enough opinions, facts, and time to provide a realistic view of the subject. I think there are readers that keep track of what I have to say but I’m under no illusions that I’m actually influencing the track of HRA.

      Reply

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