Random audio dropouts with Ultralite MK3

[sevenark]

Hi

I bought two MK3 UltraLites as part of a live audio setup a few months ago. I've been experiencing the same audio glitch on both of them - the audio will randomly cut out for between 0.5 and 1 seconds and skip. This will happen at least once or twice in a 60 minute liveset, and it occurs on both interfaces. I'm running Ableton Live 9, with the MOTUs connected via USB.

This is what I've done to troubleshoot:

1 - updated firmware on both MOTUs

2- tried 3 different Macbook Pros, running El Capitan, Yosemite and Snow Leopard.

3 - updated all Macbook Pros to the latest version of El Capitan

4 - changed all USB cables

This is infuriating - anybody have any ideas as to what's going on here? I've read some similar problems online about the issue being with OSX and the CoreAudio drivers, but there must be some way to resolve this? The system is not usable at the moment as a dedicated live rig.

Any possible solutions welcomed.

[terrybritton]

Two questions:
Are they daisy-chained? (I guess so if you have them both hooked up - using Soundflower, I imagine.) If so, what are your respective sync settings, if any? Both set to internal?

Is anything running that could conceivably mess with the timing of the S/PDIF, like some major process kicking in randomly?

I had a similar thing happening to me, and I stopped trying to daisy-chain because of it.

I just feed the analog out of one into an analog input on the second - I don't even touch S/PDIF anymore.

Terry

[sevenark]

They're synced via MIDI - it's a redundant system with two totally seperate systems. Two laptops, two MOTU soundcards running through a Radial SW8 switcher. That way if System A dies/sound card crashes etc I can switch immediately to System B with no break in the audio.

MIDI triggering (just simple transport controls, nothing more) is via an Akai MPD226. All I use it for is to move the transport locator in Ableton and press Play to start playback at a specific point on the timeline. Nothing more than that.

So I don't think that's the issue though - the glitch problem occurs even if the one system is running alone, i.e. no MIDI running at all.

There's a huge thread over at Native Instruments about something similar:

https://www.native-instruments.com/foru ... se.262889/

And this article also alludes to audio dropout problems in El Capitan:

http://cdm.link/2016/09/real-apple-news ... xed-month/

Seems to be a problem with CoreAudio in OSX??

[terrybritton]

I'm running Windows machines, and suspected it had to do with what are called "DPC Errors" where the system software or a running process suddenly takes over the entire system's resources, throwing the sensitive timing to the DACs off, making them switch off, which takes 1/2 a second or more to recover. That is why I asked about whether you used the S/PDIF, as that is another sensitive timing area.

It could very well be a Coreaudio issue as well. Or an ASIO problem, if you are using that, as it is actually quite unstable.

If you find a solution, please let me know of it - I may be able to translate it from Mackish to Windozian.

Terry