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.