What is bit transparency...?
Bit-transparency = the device (or devices in the chain) do
not modify any of the samples within the bitstream, i.e. passing a WAV through the device chain over and over again
always yields
exactly the same output WAV as input WAV.
What is your standard for something to declared "Bit Transparent"
I'm not sure who you're asking, but my personal standard: if I test it and it proves bit-transparent with my combination of gear. Or if someone else performs sufficient testing with appropriate documentation and rigor.
Also Im a bit unclear as to what qualifies as a test...
It depends on your gear. The simplest test would be something like this:
[1] Identify WAV
1 on your PC
[2] Stream WAV
1 from your PC through your known bit-transparent soundcard using S/PDIF
[3] Pass the S/PDIF WAV
1 into the CO2 S/PDIF connector and out the CO2 optical port
[4] Record the CO2 optical output onto a JB3
[5] Copy the new WAV on the JB3 back onto the PC as WAV
2[6] Trim WAV
1 and WAV
2 to the same starting/ending sample
[7] Compare WAV
1 and WAV
2 with a WAV compare utility, like the one in EAC
[8a] If the WAV compare returns no results, i.e. no differences between WAV
1 and WAV
2, then this particular test demonstrated bit-transparency for the gear combination involved
[8b] If the WAV compare returns results, i.e. identifies differences between WAV
1 and WAV
2, then this particular test demonstrated the gear combination involved is not bit-transparent
However, a single test run is not sufficient, IMO, and we must perform this test over and over and over again. How many times over? I dunno, we probably all have different standards that we would consider appropriate. And, of course, the above test does not take into account the particular gear one would use in the field. So if we proved the above combination of gear bit-transparent, it would not necessarily follow that if we replace the PC with a field ADC we would achieve the same results.
And so, testing field gear is even more difficult, and requires that the field ADC have two outputs - one to produce a control WAV, and the other a test WAV. In my case with the ODL-312, I ran my field gear as though I was, well, in the field, and determined that with my gear, in the field, the ODL-312 proved bit-transparent.