Dr. AIX's POSTS — 12 October 2014

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I finally got to the AES Exhibit floor yesterday in between paper sessions and a meeting of the High-Resolution Audio working group. The entire show was contained within one hall of the LA Convention Center, which allowed me to survey pretty much all of the vendors in a few hours.

I found it interesting to see large groups of individuals sitting in two of the corners of the open space attending seminars on “Project Studios” and “Live Sound”. How could they hope to put on seminars amidst the noise and movement of the main hall? They provided wireless headphones to all of the attendees. Mick Guzauski, an 11-time Grammy winner, was there at the “Project Studio” session talking about the use of limiters in his mixing without a PA system…just the local broadcast to those wearing the special headphones.

Today, I thought I would give a quick overview of the day. I plan to explore the individual topics in full posts over the next week or so.

I arrived just prior to the start of the high-resolution audio technical working group chaired by Vicki Melchior. There were about 15 people in attendance. Unfortunately, there didn’t seem to be much of an agenda to direct the meeting. There were ad hoc discussions of the benefits of XRCD, vinyl LPs, and direct to disc recording, which I thought wasn’t the best use of the short time we had. My contribution was a discussion or the JAS logo and whether the AES should step up and endorse (or reject) the specifications and logo being considered by the CEA.

Steve Green, the Business Development Manager for the AES organization commented about the inclusion of the DEG High-Resolution Audio sessions that were held on Friday. And he suggested that the entire convention in New York next fall would be focused on “high-resolution audio”. That was all it took for me to exit the room with him, exchange business cards, and have a very brief chat about getting the programming committee to stand apart from the DEG and get some serious discussions going about the topic. Sure it’s great to have celebrity recording, mixing and mastering engineers as members of a few panels, but it’s equally important to get accurate and meaningful information to the membership. This was a very positive sign.

Following the HRA working group meeting, I happened upon the Benchmark Media booth. There was John Siau himself with display table showing off the AHB2 Amplifiers (which he promised would be available very soon…the assembly of the units has begun), their new bookshelf speakers, the ADC, and DAC2 converters. John and I sat down and talked for about 30 minutes about a variety of topics, which is always a pleasure. One topic that he and I had briefly discussed previously was about intersample overages in PCM sampling systems…especially as it relates to Sample Rate Conversion. He explained why it is necessary to reduce the amplitude of your output digital signals by 3.5 dB to ensure that the converted signal doesn’t eclipse the bit maximum of the new file. I’ll talk about this in more detail shortly…but I found it very interesting.

I finished the afternoon by attending a few paper sessions. The first was titled, “The Audibility of Typical Digital Audio Filters in a High-Fidelity Playback System”. Although it may not be obvious from the title of the paper, this is the first AES publication that refutes the Meyer/Moran research that has been so often quoted as “proof” that CD specification PCM audio is enough for music reproduction (Meyer and Moran’s research has been widely discredited including by myself because of the lack of real high-resolution content used during the study).

Robert Stuart and his colleagues conclude: “first there exist audible signals that cannot be encoded transparently by a standard CD; and second, an audio chain used for such experiments must be capable of high-fidelity reproduction.” In other words, CDs aren’t good enough. This paper was given the top award by the AES organization. This is a very important finding.

His second paper, “A Hierarchical Approach to Archiving and Distribution” written with his long time collaborator Peter G. Craven focused on the possibility of using varying sample rates and bit depths to capture high-fidelity audio more efficiently than currently methods. Again, I’ll get back in to this topic as well.

It was a great day…meeting friends, seeing some of my students, and learning new things. I’m headed back for day three.

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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.

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