Topic: Onboard A/D Comparisons?

[jpschust]

Has anyone done an onboard A/D comparison of the basic gear we often use?  Here are my thoughts as to what should be compared (all at line level)

D7
D8
D100
M1
DAP1
D10
VxPocket
JB3

all at 16/44.1  I'd be interested to hear the results

[dmonterisi]

i think you just proposed that someone else do an 8 deck source comp and that you'd be interested in hearing the results!  excellent delegation skills!

[marc0789]

if someone sends me everything but an hhb and m1, I'll do it. But the decks are my administrative fee.  

Seriously, I've been most impressed by the m1 a/d stage, more than the da-p1 and maybe even the hhb. Smooth, grainless, just very nice.

[scb]

well the d100 and m1 are the same, so it's down to 7

[jpschust]

well heres the issue- they all need to go line in from the same source- meaning that the D/A from the original source needs to be the same (i suggest using a cd player or something of that nature).  id do it myself but i just dont have access to all those decks.

[nic]

the M1's ad stage is fine if you keep the levels relatively low(peaking about -6 or so, not higher). if you run hot levels you will notice in a wave editor that the levels on the bottom side of the waveform are somewhat "tabeled" for lack of a better word, not as dynamic looking as the levels on the topside

[Brian Skalinder]

Heh, at the moment I have a D7, D8, D100, and JB3 - over halfway there!  Ideally, I'd wanna do it in the field, not at home in front of the home stereo or straight from a playback device (CD, etc.).  I could probably run Mics > V3 analog outs > splitters up the wazoo > 4 recording devices.  Dunno if I can find time to swing this, but I may try to give it a go.  No promises, though...

[Tim]

the M1's ad stage is fine if you keep the levels relatively low(peaking about -6 or so, not higher). if you run hot levels you will notice in a wave editor that the levels on the bottom side of the waveform are somewhat "tabeled" for lack of a better word, not as dynamic looking as the levels on the topside

if this is true then I'd say the m1's adc is pretty worthless... when recording in 16bit you're going to need hotter levels than that or you're losing out on quality.

[chase]

luvean, sounds like it could be a DC offset problem if it looks as though entire wave pattern should be shifted downward.

[nic]

the M1's ad stage is fine if you keep the levels relatively low(peaking about -6 or so, not higher). if you run hot levels you will notice in a wave editor that the levels on the bottom side of the waveform are somewhat "tabeled" for lack of a better word, not as dynamic looking as the levels on the topside

if this is true then I'd say the m1's adc is pretty worthless... when recording in 16bit you're going to need hotter levels than that or you're losing out on quality.

true, I've noticed over the past few months since I havent had a "portable" pre/adc.
as long as I kept the levels peaking between 12-6 the resulting waveform seemed fine, but just a bit on the quiet side. however, I would then just apply a 6db or so gain to the waveform and it was fine.
I'm sure there are some who would say that this is not restoring any fidelity lost in the original recording, but since I dont have a high-end playback system I cant hear any added background noise, if any...have played back such a edited recording in the studio and we couldnt hear any added noise...ymmv

[nic]

luvean, sounds like it could be a DC offset problem if it looks as though entire wave pattern should be shifted downward.

if so then the DC offset is coming from the DAT and not the transfer card, but then why would it only appear with HOT levels?

[jpschust]

Heh, at the moment I have a D7, D8, D100, and JB3 - over halfway there!  Ideally, I'd wanna do it in the field, not at home in front of the home stereo or straight from a playback device (CD, etc.).  I could probably run Mics > V3 analog outs > splitters up the wazoo > 4 recording devices.  Dunno if I can find time to swing this, but I may try to give it a go.  No promises, though...

why not just do it the purest way possible- run analog out of your cd player and just keep running the same track through each of them.  no need for splitters or any other pain in the ass stuff.

[dmonterisi]

because you're trying to test the a/d's performance in a field environment.  cd's are, generally speaking, much more compressed and doctored.  in a concert recording environment, the wider dynamic range could pose different issues for a a>d than recording from a cd.  

[jpschust]

alright fair enough.  the issue is getting the same quality of source through every single A/D in the same exact setting.  even with the compression and range of a CD, it would be better to be testing just basic tones.  if ya wanna be really pure about it also test white and pink noise

[dmonterisi]

you're absolutely right, but if you're gonna do this test, might as well do it right.  i don't particularly see the value in it at all in this late stage of the dat game, but that's just me.