Dr. AIX's POSTS — 06 June 2014

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I used to spend long hours working in my studio. Early in my career, I worked on commercial records that took months…sometime many months…to complete. Studios generally don’t have windows. The musicians, engineers and producers that craft the records that we enjoy spend countless hours in the studio struggling over all of the elements that go into making a great record…and they rarely see the light of day.

A typical studio books two sessions per day. At least that’s the way it was back when I was doing that kind of work. There were sessions during the day followed by an evening session. Occasionally, bands would “lock out” a studio for days, weeks or even months, which meant they had exclusive rights to the studio, engineer and equipment 24 hours a day. Having a room locked out meant that you didn’t have to “clear” the board (return all of the settings to their nominal or neutral position), remove all of the patch cords and put away all of the equipment. In the day’s of analog consoles, this was a huge advantage because you could end one day’s session, take some time to sleep or eat and return to the room and pick up right where you left off.

The endless days of working on a single track drove me a little crazy. During one year, I worked on only two records. Every day meant I listened to the same tunes over and over again as we added parts and refined the productions. That life might work for a person in their twenties or thirties but it didn’t have long term appeal to me. I moved to mastering and opened up Pacific Coast Sound Works in 1989.

Mastering requires a completely different sensibility…and much shorter sessions. Mastering studios have the last word in the sound of a particular recording. The engineers that master stereo or surround mixes make sure that all of the tracks on an album reflect the same “sonics” and that they match the current standard for fidelity, timbre and level. That can be a good thing in some cases but it can also destroy a great performance and recording as well.

Working in a recording or mastering studio exposes the individuals working inside to sound over many hours…and usually at levels that are too loud. The reference standard for film mixes is 85 dB SPL but many tracking or overdubbing sessions exceed that amplitude by a large margin. Ear fatigue is a real thing. After 5-6 hours, I found my aural acuity diminishing. If I couldn’t fine tune a particular sound or track because of long term exposure to elevated levels, my productivity suffered…as did the product that I was working on.

Over the thousands of hours that I’ve spent listening to music produced by analog and digital systems, I’ve noticed certain physical and psychological changes. And those changes were different depending on whether I was listening to analog tape recordings, standard resolution or high-resolution audio digital tracks. Mind you that I have no scientific evidence for these observations but they have been predictable enough to warrant sharing them here.

Analog tape, in spite of its lack of dynamic range, never gets old. I can listen to analog tapes endlessly and never experience any noticeable negative effects. Yes, I’ve gotten tired and needed time away from a particularly long period of listening but there was always a natural and “warm” euphonious feeling that accompanied analog tape.

Standard resolution 44.1 kHz / 16-bit compact disc PCM digital recording is different. I have probably mastered 500 albums during my career. They span heavy metal, hard rock, jazz, pop records, acoustic and classical albums. After carefully listening to any type of music over 5-6 hours encoded as Redbook standard audio, my body tells me to take a break. The sound of standard resolution digital can be clear and dynamic but there’s something happening in the sound that affects me…and not in a good way. I can’t describe it any better than to say I noticed a difference once I started mastering CD professionally instead of creating new tracks using analog tape.

High-resolution digital, on the other hand, presents an entirely new level of sound capture and reproduction. I have sat in my room and listened to unprocessed 96 kHz/24-bit PCM audio without any negative physical or psychological effects. It’s like being back in the luxurious sound of analog tape without the noise and distortion.

I know this purely anecdotal but it comes from my experience as a professional audio engineer with over 40 years of experience. Take it for what it’s worth.

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About Author

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.

(19) Readers Comments

  1. Mark,

    The same thing happens to me. Listening to CDs for a long period causes great distress and a desire for silence but listening to tape, vinyl, or 24/48 on up has no adverse effects. I have the somewhat crazy theory that CDs cause my brain to work too hard, perhaps filling in some gaps, so to speak. The really odd thing, though, is that I can rip a CD, put it into iTunes, then play it back through my Squeezebox Touch and never get tired of listening. Though all the nuances are there, it’s as if the Touch rendered the CD “analogue.”

  2. Interesting. For your reaction to 16/44.1 recorded audio, a description of listening fatigue I think.

  3. Mark,
    In terms of sample rate, what do you believe accounts for the more “relaxing” presentation of 96/24?
    Thanks,
    Paul

    • Paul…I’m not sure. This is me at my most unscientific. There must be something in the high-frequency domain that is not completely accurate to the real thing.

  4. If the sampling rate was 48kHz were you still fatigued after a few hours?

    • I can only relate to this from my years of being a mastering engineer…which was always done at 44.1. I haven’t spent enough time to say anything abtou 48 kHz.

  5. Hi, Mark!

    You nailed it!!! Absolutely. Thanks a lot for sharing with all of us your experience.
    We’re getting closer to define hi-def. I think it will always stand in the realms of perception (obviously it’s scientific, but for the masses it’s perceptual).

    You make a very important and crucial point: as many of us, you can go on forever with tapes and limited SPL’s. And I’m sure that applies to all ears. What happens -as you describe it, when listening for prologed sessions to Redbook standard tracks is physical! It puts a burden in our biology… and I’m quite sure it could be demonstrated that the neurological effect is massive. Not with hi-def, good quality audio.

    I recorded some tracks for Apocalyptica live a few years ago, when they only used cellos. For the ones who don’t know this band, they play heavy metal rock on cellos, with incredibly sharp pickups and all sorts of distortion.

    I did it on tape and on PT-HD 192/24. When we mastered the stereo final, we kept one on tape, one on 96/24 files, and then we dumped the whole thing to Redbook. Not even the band could listen to more than an hour to the Redbook tracks. We could go on forever on tape or HD.

    I guess you found, along with all the science behind hd-audio, the real worth of listening to hd. It’s physiology, physics and psychoacoustics what makes it so important and why it should become a standard. Let alone that musicality increases palpably when the whole process is followed within hd standards.

    Kudos! I loved this post… maybe the best ever! And many thanks for sharing!

  6. Very useful, and thoughtful thoughts there, Mark – and with all your experience, much respected.
    Thank you, Anton

  7. The second paragraph of this post (talking about leaving settings and resuming later) reminded me of a news story I heard on NPR about the 50th anniversary of the Beatles Ed Sullivan Show debut. Not widely known is that that was actually the second concert that day (the first was basically a sound check for the broadcast and was not televised). The Beatles’ and CBS’ sound crews spent the whole day getting the settings ‘dialed in’ (taking into account the screaming girls, thus the soundcheck concert), marked the pot settings on the board, and went to dinner together. When they returned, they discovered that the cleaning crew had zeroed all the pots and wiped all the chalk marks off. So the biggest live musical broadcast in history up to that point had to be done ‘seat of the pants’ style.

  8. love this post, quite fascinating… (an intriquing reminder of how ‘physical’ sound really is)

  9. Why not prove it scientifically then? It’s entirely possible even with long listening sessions.
    Also a neat little trick is to apply a steep high pass to the music, let’s say starting from 20kHz. What do you hear after that? If the playback system is high quality I guarantee – you wont hear anything. So what can be significant about something that we literally don’t hear at all? We don’t know is a possible answer – but that is exactly the reason why we need credible evidence that the fenomenon really exists.

  10. Hey, Doc: Did you see the opening column in this month’s TAS? The matter of provenance and putting old wine in new bottles was addressed, and the author— Robert Harley, I believe— appears to be in line with you. He does contend that analog tape is hi res, but that does not detract from his concern that record companies have a chance to either offer real hi res material to download services or not and say that it is. I am encouraged to read this. It seems that your position is gaining traction in the audio community. Huzzah!

    • Scott…I got an early copy of Robert’s column and know that he’s in agreement about the provenance thing. His belief that 8-10 bits of PCM dynamic range from analog tape is “high-resolution” is misguided and only further dilutes the realities of high-resolution music. He knows that if a strict standard for HRA were to be put in place that most, if not all, of the content coming through HDtracks and other would be labelled as “standard resolution” and that would be bad for business.

  11. Interesting post. It should note, that ADCs and DACs are better now, than, say, 10-15 years ago. I don’t hear digital harshness from my Lynx Hilo converter even 16/44.1 resolution.

    • I don’t hear it either…but after hours of high-resolution vs. CD standard audio, there is something different.

      • Do you think, that this happens also with converters we are using nowadays?

        When I listening 16/44.1-records several hours a day at my home, all I want to do after that is listen them more. Of course this is not a same thing, as listening same records day after day in studio. We all have different ears, also.
        🙂

        Very interesting subject.

        • It’s hard to know…I haven’t been doing long mastering sessions for a while.

  12. Mark,

    You realize that what this piece says is that while – according to Nyquist’s theory – 44/16 is good enough to capture whatever is on tape, you’re actually feeling what I’ve been saying – and you’ve been pooh-poohing – that more than two samples per cycle really is better.

    That’s why 96/24 is less tiring: because it’s drawing a clearer picture of the sound waves below 22Khz than 44/16 can do. Whether it’s because the brain has to work harder to reconstruct the sound wave when given fewer samples (which may not always be aligned with the peaks) or something else, close listening to a coarser image is like enlarging a digital picture – eventually the underlying grid may be felt , even if not consciously perceived.

    The implicit corollary of this is that rather than warring with the reissue sites over the making of 96/24 transfers of analog masters – which should be less tiring than CDs to listen to, even if you can’t find any higher frequencies in their spectra – you could focus your attention on the decibel war, which folks do understand.

    If you grant that the analog flat masters – the mixes as they existed before the dynamic range compression added in mastering – are worth getting a careful 96/24 or 192/24 transfer, instead of calling re-issued classic albums not worth the money being charged you could lead the industry in not just labeling for provenance but also for the amount of post-artist mix compression, and show them how good that could sound.

    That was a large part of why the old Mobile Fidelity Half-Speed Mastered LPs sounded so good: they boasted that they did not use any volume level compression, and kept the noise floor low to enable that by using vinyl so clean that their disks were translucent.

    Given that folks who pay for something extra are unwilling to believe that they wasted their money, and that not a lot of folks have systems that would reveal its absence anyway, it’s far less likely that high def audio will be stalled by the presence on the market of “not fully high-def” product than that it will be stalled by squabbling among providers about whose products are worthy of the name. That begins to look like the DVD-A / SACD battle, which was won by nobody.

    As a content provider, you should say: “However you want my mixes, I’ll provide them. I like PCM better, but you can download my stuff in DSD if you want.”

    • Phil…I have no scientific explanation for why things “feel” better after hours of listening…but Nyquist still stands. Two samples is definitely NOT the reason! There isn’t any additional work required to “reconstruct” the sound wave…these are facts that are not open to debate.

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