Motu 16A ADAT 4 channels only

[stewartadam]

Hello,

I have a Motu 16A and suddenly when I go to Pro Audio Control to make changed in the ADAT settings I only see 4 channels of ADAT on each of the A and B settings. How do I get this back to 8 channels each?

Thank you

Stewart Adam

[CharlzS]

What sample rate? A single ADAT connection carries 8 channels @ 41/48K. If your rate is 88/96 you'll only see 4 channels over one connection. You need two ADAT connections via SMUX to see all 8 at higher sample rates.

[monkey man]

It's as Charlz says, mate.

88/96kHz exploits double the number of ADAT channels to carry the data at 44/48kHz per-lane, but it's recombined transparently into the higher SR's once received .

[stewartadam]

Got it! Stupid me. Thanks for your help.

[monkey man]

Hey, not stupid at all. I've seen many folks scratch their heads over this. It's one of those things - if you're not aware of the ADAT format's 1 x SR per-lane limitation, something would definitely seem amiss.

My guess is that at the time of development, these modern, higher sample rates weren't anticipated as being relevant any time soon. After all, the ADAT and ADAT XT units, as well as the direct competitor's gear (Tascam), ran at "1 X" rates - 44.1 and 48kHz respectively, IIRC, and sounded great, especially "for the time"... and money. The bump in quality and lack of noise were something to be marvelled at back in the day, so it's no surprise that folks didn't necessarily anticipate a hunger for higher SR's down the track.

[bayswater]

and sounded great, especially "for the time"... and money.

I'd say not just "for the time". I have a DA-38 and had the use of 3 DA-88s for a while, and I still think they were the best sounding I've used, taking both D/A and A/D into account. They recorded at 18 bit and dithered to 16 on playback; that might have helped. But they're just too inconvenient, TASCAM doesn't support their products for very long, and it's difficult to find people who care about "the sound".

[monkey man]

Indeed, Stoivo.

Even my blackface ADAT, which was 16-bit (pre the 20-bit ADAT XT), which we all knew didn't sound as good as the Tascam units, sounded fantastic. If I pull up the demos I did back then I still marvel at the clarity and "honesty"... and, surprisingly, the "emotion" that unit captured beautifully.

Ahh nostalgia. Even taking into account the possible contribution thereof towards this impression, those units, including yours of course, still stand up extremely-well IMHO.