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.

5 thoughts on “Roadtrip to CAS 5 in San Francisco

  • Hi Dr. Aix,
    I enjoy reading your daily emails. They are very educational, as I am a novice audiophile.

    I have a question about something that confuses me: We speak about sampling rates in digital recording. I understand about the 44.1k, 96K, 192K, etc. and about word length.

    My question is regarding streaming digital sources, such as Beats, Spotify, etc. How does “bandwidth” affect playback quality, and why? I imagine that even a 192K, 24bit sample streamed over a lower bandwidth channel would sound poor, but why, since the original digital content is 192K/24bit. In other words, how does bandwidth on streaming audio affect the fidelity of the source?

    Also, is there any way for a consumer such as myself to know with any reliability that the streaming source I am paying for is, in fact, using 320kps bandwidth, rather than a lesser bandwidth. Beats claims 320kps bandwidth, but can this be objectively verified? In general, are some music streaming services of higher bandwidth than others?

    Hope you enjoy the SF show. No hurry on the answer.


    Mitch Miglis

    • Here’s the quick story. The specifications of encoding analog signal into digital ones using PCM have the parameters you mentioned…both sample rate and word length. When streaming audio, we talk about the bandwidth required to transmit a digital file from one place to another. If we wanted lossless PCM audio at Redbook specs, our pipe would have to be capable of 1411 kbps….without any dropouts. Streams that are limited to 128, 256 or even 320 kbps use perceptual masking and other data reduction techniques to reduce the 1411 kbps of the CD into the small pipe of 320 kbps. This changes the fidelity of the audio. The highs are reduced since they take up a larger part of the bandwidth than low frequencies.

      It’s always best to start with a high quality source file…but the final streaming codec will define our much quality is actually transmitted.

  • I think I might be able to attend CAS this Saturday…. Hmmm, ticket prices are reasonable..

    I believe this is like 5th time on attending on audio meetings/shows, which always have been rather disappointing. I hopefully this time might be a bit different.

  • Craig Allison

    Mark, you are cordially invited come on up to the Wine Country and visit me at Lavish Hi-Fi in Healdsburg. We’ll have a great time, guaranteed.

    • Thanks for the invitation…it would be lots of fun but time is tight, we have the puppy and plans with friends in the Palo Alto area.


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