Computer/Digital Audio Information Sources
Dec 22, 2004 at 12:34 PM Thread Starter Post #1 of 4

jxb2

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I'm a 56-year-old who built tube amplifiers and did Ham radio as a kid (WB2BIU), but who is a boob regarding computer and digital audio (I quit in disgust when the transistor became the rage 40 years ago - the first KLH transistor power amp was three angry cats in a small box, horrible when transitioning from KLH 9 electrostatics driven by early Futterman).

Can anyone point me to some Web sites that have an overall description of the issues regarding using a computer for music playback (no interest in recording, though would like to copy my analog and redbook DC collection). I got EMU 0404 last week and instantly noted improvement over soundblaster, especially running into Gilmore Lite, but 0404 has controls and switches (and names for things) that overwhelm my little point-to-point wired mind.

Am good with computers and software, so don't need handholding in that area as well - just have anolog brain wanting to understand (and at least try) digital audio world.

Thanks for any help.
 
Dec 22, 2004 at 9:44 PM Post #3 of 4
Copying CDs to disk is best done directly via a good optical drive (working C2 error correction support recommended) and, say, EAC for getting as close to bit-perfect as possible. When archiving vinyl and other analog sources you won't get around recording and cutting the stuff, but the 0404 is certainly sufficient for recording purposes. Back when I recorded some LPs several years ago with my trusty Pentium 75@90 and a crappy OEM Aztech ISA card (the stuff is surprisingly decent sounding nonetheless) it used to be quite a long and tedious procedure, today it should be somewhat more fun.

What's important in the digital audio world? Well, for the absolute basics (PCM, sampling theorem etc., as far as needed here) there'll probably be literature covering this. Real-life quality issues typically have to do with the quality of A/D and D/A converters (relevant measurements: dynamic range, THD/THD+N, IMD/IMD+N, ...; a spectrum frequently tells more than a thousand words), opamps (typically 4580s today, frequently more relevant for the sonic signature than the DAC itself) and the classics like caps (you do not want tantalums in the signal path, for example, these are pretty nonlinear; see datasheets and app notes from DAC manufacturers - Cirrus Logic, Wolfson, AKM et.al. - for stuff they recommend). Power filtering (and, I guess, shielding) is also very important, given PC power rails are usually pretty dirty. Then there's the area of jitter which can lead to FM distortion, and finally the board layout and jacks that are not to be forgotten either (cards with 3.5 mm jacks frequently exhibit reduced channel separation in the highs due to unwanted capacitance). Something which typically only bothers DAC manufacturers (and the diyaudio.com crowd
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) today is lowpass filtering to avoid aliasing.
The typical data flow in a sound card is: bus interface / DSP (one chip, typically) --> DAC+ADC or codec or ASRC as transceiver for digital transmission.
I hope you have enough search terms now.
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BTW, you're not the first one to find the E-MU software somewhat... complex. That stuff is targeted at musicians with some computer experience after all, so one may be somewhat lost as a layman. Ordinary consumer sound cards' control panels tend to be more intuitive...
 

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