Yep. That's one reason I don't like them. The other is that they're not
at all as powerful as the resellers want us to believe. Any decent Alpha
workstation would beat most of those machines easily, probably even on
processing latency with a proper RTOS. (Alphas are used as DSPs on cards
for very demanding signal processing tasks, so I'm not speculating
here!)
> Second of all, I don't think you want to get analog anywhere near
> a computer. Think of all the electrical noise.
Basically, I agree, but the performance of some new audio cards makes me
less confident that digital noise is really so impossible to avoid.
People have measured around 115 dB SNR on the Gadget Labs Wave/824,
which is a very affordable 8 channel, 24 bit cards WITH CONVERTERS ON A
BOARD IN THE COMPUTER! They use very low impedance (VLZ) cirquitry and
an analog cable to the external box.
As a comparison, my Layla (external converters in the rack box, 20 bit,
costs a lot more than the 824) has about 98 dB SNR. Imagine the
possibilite performance of a true external converter, built the right
way, using the best chips... I think that'll do for most users, really.
> If I actually cared about perfect audio, I'd do a D->A conversion
> inside the microphone. I'd oversample for both time and space,
> then downsample inside a custom board. Other than the input itself,
> nothing anywhere near an audio frequency would be allowed near the
> microphone or cable.
There is no such thing as perfect audio IMO, but you'd probably get a
lot closer by eliminating most of the relevant problems with *real* high
end digital audio: The analog noise... That would be pretty cool, and as
"silicon is free" and Sigma-Delta converters need no trimming; only a
low-jitter clock, digital mics shouldn't be too expensive. (You have to
compare that single item to a mic, a pre-amp and a converter to be
fair.)
Well, now we are pretty off-topic, I think...!
//David
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