Dr. AIX's POSTS — 24 November 2014


Another new moniker for high-resolution audio, except this time it’s specifically for live sound…it’s called SLA or Super Live Sound. And lest you think that someone has finally solved the problem of horrific sound at live concerts, let me tell you immediately that this is just another exercise in marketing and spin. I’ve read the spiel from this company before but a recent reader comment reminded me that DSD got roped into the world of live sound in addition to recordings.

Feel free to read the pitch for yourself (click here for the article) but for those who want the digest version, here it is. The KV2 company deals with acoustic design and live sound system design and deployment. They’re site claims that they are defining a new standard…the previously mentioned Super Live Sound.

Here’s the opening sentence from their piece on Dynamic vs. Sampling:

“Live audio is very dynamic, yet a dynamic range of 130dB is almost impossible for any digital AD and DA converter at the current sampling rates used to replicate. Dynamic resolution is directly related to the bit and sampling rates used in the digital conversion process.” They’re associating sampling rates with dynamic range.

Think about it for a second. Does anyone really believe that the potential dynamic range of a live concert venue (I’m not talking about Disney or Zipper Hall) can approach 130 dB? They most certainly don’t…nor are the FOH (Front of House) mixers allowing that much dynamic range through the output busses of their consoles. They use compressors and limiters as much as the guys in the studios…may more…if that’s possible. However, at 24-bits the dynamic range of modern AD and DA converters does get to 130 dB. But is this what you want at a live concert. They should be talking about SPL (Sound Pressure Level) instead of dynamic range. Just how much energy do you want to come out of the speakers?

The dynamic range of a typical live amplified concert is less than 30-40 dB…not even as much as a CD.

They mention the term “dynamic resolution”, which is not part of my normal lexicon of audio measurements. We use decibels to identify relationships between loudness and energy levels. And we also use decibels to measure absolute energy levels referenced against 0 dB SPL. I’m not aware of “dynamic resolution” being defined.

Here’s a good line from the website page:

“By increasing sampling rates the amount of transferred information increases, but sampling rates cannot be unlimited, so digital audio can never reach the quality of a high definition analog system.

They want to raise the sampling rate to ultra high rates because they believe “At the current sampling rates utilized in commercial audio system design it is evident that their resolution is compromised as the frequency range increases.” The claim that detail and ambiance are lost if you don’t raise the rate to 20 MHz! Yes, 20 MHz or 7 times higher than SA-CD. We’re back to pitching the DSD format except now it’s for live sound reinforcement. At least they’re not trying to push 20 MHz as downloads.

The KV2 company advocates taking the “pristine” analog audio coming from the mixing console and digitizing it to 1-bit DSD (with a special step compander to get more low level detail and 20 dB of additional dynamic range) at 20 MHz. Then they do their digital signal processing (remember you can do anything to 1-bit…so they must be going multibit) before sending it to the analog outs and speakers.

I’ll come back to this tomorrow…they’ve got some great graphics that confuse things even further.

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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.

(7) Readers Comments

  1. From their graphs and description they seem to be alluding to the sinc function. However it all looks like a load of pseudo-scientific mumbo jumbo (although anyone who has the time to follow this rabbit down the hole may correct me).

    They’d be better off taking the subjectivist route, rather than trying to make claim to engineering credibility.

  2. I’ve come up with a new acronym: TPA, for Tea Party Audio.

    Their motto is “My mind’s made up, don’t confuse me with facts.” (One of my mother’s best sardonic coinages.)

    Once you recognize this, you can let your blood pressure come down.

    Nobody’s going to be able to persuade the DSD TPA crowd of anything inconsistent with what they already believe.

    • Thanks Phil…audio is just one of those things that people like to debate.

  3. Have you looked at the products on their web site? The only thing I could find that has their “Super Digital” logo is the SDD3 super digital delay line. Look at the spec sheet for it.

    Channel Crosstalk 90dB
    Signal to Noise Ratio 105dB
    Total Harmonic Distortion 0.005%

    Seems like poor performance. Nothing like the Benchmark equipment. So a load BS.

    • It’s just another site full of hype and spin.

    • I hadn’t seen Craig’s take on High-Resolution. I know him and will read the piece shortly.

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