Dr. AIX's POSTS — 16 January 2015


I mentioned briefly in my first post from the 2015 CES Show that David Chesky introduced me to his Ph.D. friend Edgar Choueiri on the first evening of the show. This is the guy that has updated the use of binaural recording and reproduction technology so that it can work in a room driven by only a couple of speakers. While the rest of the world seems content on elevating headphones as the ultimate way to experience recorded music, Dr. Choueiri wants to bring the world of 3D audio into your living room…and he seems to be making some progress. This is one of my doctoral areas of study and thus I’m very interested in what 30 years of technology advancements have brought to binaural recording.

When I entered the room and met the professor, he picked up a vintage stereoscope and handed it to me. This is what we are doing…only we’re working on the sense of hearing rather than sight. In case you haven’t been rummaging around your local antique store looking for a stereoscope, you may be more familiar with the updated children’s toy versions that had discs to deliver 3D visual stories. They looked more like binoculars, you held them up to the light and presto, and the images really did appear in 3D space. The magic happens because the content intended for the right eye gets ONLY to the right eye and the left content gets only to the left eye. That’s the miracle of 3D movies in the theaters or at home.

I couldn’t sleep last night and ended watching the Martin Scorsese directed movie “Hugo” last night from midnight to 2 am on my 65″ Panasonic. It paled in comparison to the 3D IMAX version that I experienced when it was first released. I’m a big fan of 3D done right…if you haven’t seen “Hugo” in 3D, it’s on my highly recommended list.

Dr. Choureiri’s system is called BACCH-SP and is available for purchase a selected high-end audio retailers. The SP stands for stereo purifier. The retail price is $55,000. But what does it do?

While I was waiting to get a chance to experience the 3D sound demo, David Chesky positioned himself in the single chair in the demo space while Dr. Choureiri did a few measurements. It seems the key to getting the best possible experience from your processor is to fully calibrate the unit to your individual situation. This includes setting up the speakers in the exactly the right place. In the demo room, they rather small speakers were not more than 4-6 feet away from the listening position. Then there’s the head tracker. Yep, the unit uses an infrared head track that follows the position, rotation, and elevation of your head as you move around in front of the unit and playback speakers. The setup is done using an iPad app and it establishes physical limits to how far you can move before the crosstalk cancellation ceases to work.

I’ll keep writing on this tomorrow…got to get my late afternoon nap.

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About Author


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.

(17) Readers Comments

  1. This sound to me like a modern and more expensive version of the Sonic Holography as done by Bob Carver back in the’80s.

  2. “retail price is $55,000”

    Mmm..no thanks. 2048X Oversampling is already delivering a perfect 3D sound scene, according to Mr. Watts from England.

    “Hugo” in 3D

    Had you simply Trimension DNM turned on ?

  3. Mark wrote: I mentioned briefly in my first post from the 2015 CES Show that David Chesky introduced me to his Ph.D. friend Edgar Choueiri ib the first evening of the show.

    What’s with the emphasis on the PhD? Couldn’t you have just wrote: I mentioned briefly in my first post from the 2015 CES Show that David Chesky introduced me to his friend Edgar Choueiri. Are we supposed to be wowed by the PhD bit? Whilst much research does contribute to human knowledge, particularly in medicine, there’s a lot of total BS put out there as well particularly from those who have gained a PhD – one of my PhD colleagues put it quite succinctly a few years ago: “trust me I’m a doctor”. In the UK a PhD can only be gained from research (in the US I believe it can be taught – don’t get that), but it annoys the hell out of me that in the US, once a person who has PhD has been mentioned everything that person has done must be then taken as gospel, rubbish. Please stop the PhD name dropping, it means nothing.

    • Dave, getting a Ph.D. is not a trivial achievement…I know I’ve been through the process myself. I studied for many, many month for my qualifying exams (both written and oral), did two years of research and creative activity, and made it through my committee oral exams. I will grant you that it doesn’t guarantee radical approaches but it does mean that someone stuck it out, met the requirements, and gained entry into a rare club. Of course, it’s not the only way to gain knowledge or become an expert at something. It’s the same in the US, you can’t earn a doctorate without doing original research or creative activity.

      I won’t stop granting the appropriate respect that Dr. Choureiri and others deserve by addressing him as Dr. or using the Ph.D. designation. Having a Ph.D. does mean something…but not everything.

      • Having done 10 years post-doctoral work and the remainder in industry I’ve seen it from both sides. In my field of engineering consistently the best research papers I see are from those working in the R and D departments (some with PhDs many without) of companies; because funded/impacting the company’s bottom line, the research tends to be incremental and genuinely useful. Contrast this to university blue sky research which is generally there for self perpetuation, i.e. to generate funding from whatever research council to fund itself through activity and publications.

        I’m not arguing that getting a PhD takes time, patients and a great deal of effort (I’ve known a few people who started but never finished), but it does not automatically grant the holder of a PhD expertise in that field (or a very narrow aspect of that field).

        I have no problem with you using a person’s title, however it implies they are at the pinnacle of knowledge in the field of work being discussed; this is misleading.

        • You get no argument that a doctorate doesn’t guarantee expertise…but as a member of the club, I’m willing to give other members a level or respect that you seem unwilling to do.

          • With respect, as holders of a PhD we are not members of an old boy (or girl) club. We are note entitled to respect just because we hold a PhD. Respect is earned and the best way to earn respect is through the work we do, not through our titles. My best work, to date, has been to enhance the way a UK manufacturer of propulsion systems (aeronautic and naval) do their fracture mechanics. The methodology came out of my first year of studying for my PhD and could have been done by anyone who understood basic contour integration; this was real research which genuinely pushed forward how we did things, not the blue sky stuff.

          • The fact that one has earned a Ph.D. makes them a “member” of a a select group of individuals that have been through that rigor. I didn’t use the word “old” anywhere in my statement. But I disagree, we are deserving of a certain amount of respect because we attained the highest academic degree….getting their involved a great deal of work just like studying independently. And I’m not sure that doing “blue sky stuff” is a bad thing either. Who’s to stand in judgement of another persons work? Are you saying that my degree is worth less because I composed a musical composition rather than doing engineering? I hope not.

      • Carmack isn’t Ph.D. but also launches rockets.

        Briefly put, real audio doesn’t need 3D sound auxiliary, it only requires a proper upsampling level.

        • Jay, I’m not sure I can continue to approve your comments. They don’t hold much weight or accurate information.

          • But as a light aside, Jay’s posts do make entertaining reading.

        • Mark wrote: “Are you saying that my degree is worth less because I composed a musical composition rather than doing engineering?” No, I’m not saying that, nor am I getting personal. Wikipedia explains blue sky research rather nicely.

          • There really should be an edit button, anyway.

            Mark wrote ” Who’s to stand in judgement of another persons work?” Firstly, we do it all the time it’s called peer review; secondly I have the right to scrutinise (and criticise if necessary) anybody’s work whether it be research, a book, a play, a movie or whatever. If I see something which I don’t agree with, for whatever reason, I have the right to say so.

          • And remember that there is a committee of faculty members to review the research along the way. Not all things survive scrutiny, I know I challenge research all of the time…my favorite is the Meyer and Moran mess up. Let’s move on.

  4. Indeed, let’s.

  5. Hi Mark,

    Dr. Choueiri mentions that Binaural recording would be the optimum recording method in order to take advantage of his BACCH filter, but I was wondering if the microphones used in or with the currently available dummy heads (B&K, HEADacoustics, Kortex, Kemar, Neumann, etc.) are HRA capable?

    As far as I have been able to find out, neither the B&K or the Neumann meet HRA standards, but they should meet the standards that account for the tests for which these dummy heads are usually put to use. I’m not sure if these test standards meet the criteria of matching or exceeding the parameters of human hearing, but it would make sense.

    My underlying question is of course if it’s possible to make true HRA recordings – as you define HRA – with the current available state of the art gear for Binaural recording?

    On another note, one of my favorite small labels – one you should definitely check out in case your not familiar with it -, Carpe Diem (http://www.carpediem-records.de/en), run by Tonmeister Jonas Niederstadt, has just released its first recording in 5.1. Jonas has not notoriously been an HRA champ, but his recordings are just as fantastic as Morten Lindberg’s (although with more modest gear and no DXD endorsements).

    Only a few of his recordings are available in 24/96 or 24/192, and now his first release in 5.1. I have the stereo version of this fabulous recording, and I was thinking you might check out Niederstadt’s work and see if could find a place on iTrax. When it comes to processing, mastering, compression, etc., he seems to be your kind of guy – my guess is minimalistic or none at all… but I guess only a Spectagram will tell.

    Here’s his brief announcement of the 5.1 release on FB:

    “Tonight, Anne Hytta will play the first DRAUMSYN concert in Germany at Radialsystem V, Berlin. To celebrate, I have finally put the 5.1 Surround Version of the recording online for purchase on our website. It’s a 96Khz/24Bit multichannel FLAC and the sound is incredible. I used 5 microphones for the recording, which are played back over the 5 speakers: no mixing, no artificial reverb. Just pure hardanger fiddle sound in a lonely ancient Norwegian stone church at night. Enjoy. (JN)”

    Keep those juicy and provocative posts up and take care of those lungs.


    • Thanks Camilo. I will certainly check out the Carpe Deim recordings…thanks for the recommendation. He does seem like my kind of engineer.

      As for the binaural heads and the microphone specifications. All microphones continue responding past 20 kHz but the output begins to suffer because they are not optimized to function well in the ultrasonic range. The whole BACCH binaural thing by Chesky and Dr. Choueiri is less about high-resolution and more about 3D immersive sound.

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