MOTU 828mkii (again)

Input volume control for ADAT inputs

Well, I have another question already. I am attempting to dump tracks from an ADAT tape deck via lightpipe to the ADAT inputs on the MOTU. My VU meters on the ADAT do not reach 0db, but the n-track input VU’s show a hotter signal and are clipping. I cannot find any place to control the output volume of the ADAT/MOTU or the input at the n-track end.

Any ideas are appreciated.

I don’t have the 828 but we use a MOTU 24io at church. I think there are trim and/or level controls in the CueMix console that should do the trick. Did you check the CueMix Console carefully?

D

Well … there is no way to attenuate the ADAT inputs on the 828mkII and I’ve never had the pleasure of working with an ADAT tape machine (can’t help with that).
If the tracks aren’t clipping on the ADAT deck, they shouldn’t be clipping in n-Track (I would assume it’s just a transfer of the digital data).
Do you have the 828’s clock source set to ADAT Optical in the FW Audio Console?
How do the meters in CueMix, for the ADAT channels, react with the faders all the way up?
Are any of them clipping?
Even though CueMix is just a monitor mixer, having the faders at Unity/0 might give an idea as to what kind of signal is coming into the MOTU.

I really can’t think of why a digital signal would clip if it weren’t clipped already.

I believe you are right that the 828mkii has no method of attenuation for the ADAT signal. Digital should be digital. I think you are also right that the Cuemix mixer is only for monitoring. I may turn them up just for fun and see what they indicate.

I don’t remember what I had set as the master clock, but I think it was set to ADAT.

I also tried setting n-track back to 16-bit. That didn’t seem to make any difference.

I only have one song where a track is getting clipped. I don’t hear any digital distortion on the ADAT, but it sure sounded bad on n-track. If I need to, I’ll take the analog signal from the ADAT and run it into the 828mkii. The content is not that important. Just a song I did a few years ago that I want to convert to another format in case my ADAT tanks.

Thanks for the suggestions.

There really should NOT be a way to adjust the volume of ADAT inputs.

You see, the ADAT signal is already digital. Adjusting the volume won’t avoid clipping – the recording is already clipped and there’s no getting around that. Changing the level woudn’t improve the signal quality at all (in fact, it would reduce it slightly, though not enough to matter).

Once you have the tracks in n-Track, you can then do any necessary adustments. These adjustments will happen internally in 32-bit floating point format, which means that you won’t lose any of the fidelity of the original recording. Likewise, you won’t be able to recover any fidelity you lost due to inappropriate record level settings when making the ADAT recording. You can soften the clipping using various filters or hand-editing the clips in a wave editor like Audacity.

Note that I said there should be NO change in fidelity between the ADAT recording and the tracks after being passed to n-Track. If you do hear a difference, then something’s amiss, or else you’re using different gear to monitor. It might be that the audio outs on the ADAT aren’t very good and covering up the clipping. Or it may be that after importing the tracks to n-Track you’re not mixing them correctly and you’re getting clipping in the output stage.

Try to find out more why you’re hearing the clipping with n-Track and not the ADAT. The tracks in n-Track should be bit-for-bit identical to the tracks in the ADAT! So something else is going on, and you need to figure out what THAT is.