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Hi all,

Yesterday I had a charity event for breast cancer research. I played in the courtyard of a true medieval castle.

Setup: 2x Denon SC2900 (latest 1140 firmware), Denon X1600 mixer, MBP 15" (freshly reinstalled with latest OSX version and updates). I had the Denon's hooked up with a (non-powered) USB-hub. The other USB port on the MBP had the external HD I use. Since the 2900s have their own power, there should not really be a reason to have a powered USB hub for them, as they don't take power from USB (like a memory stick or external 2.5" HD). I tried the entire setup in the warehouse for a few hours the day before. Everything worked fine. During the gig though I had the following problems:

1) Unexpected shutdown of Cross (happened about 4 times during the night). It SEEMS that it happens when I switched off one of the 2900s in order to restart it. Will check to see if I can reproduce.

2) After restarting Cross from unexpected shutdown, I couldn't load tracks anymore (check audio settings message). I tried rebooting the 2900s, then restarting the software and even rebooting the MBP. In various order. No luck. I ended up removing the aggregate device, starting Cross and setting audio to internal and mixer to simple stereo (or dual stereo, can't remember). Then powering EVERYTHING off and restarting. Then making a new aggregate device. Then start Cross and set audio to aggregate and mixer to external.

3) After having everything up and running again, after some time (happened twice, once after about 15 minutes on my left deck, second time during the 2nd track I played on my right deck) the sound would become horribly distorted. Only thing to do was what I described at 2), redoing the whole thing.

4) At one point I could browse from left deck, select/load track into player A, but when I pressed play it wouldn't play. When I hit cue I saw the waveform "jump" a little, but holding cue didn't start playback either. Switched the SC2900 back to CD and it wouldn't do anything anymore. Something "crashed" the 2900.

I had a bit of time to to fiddle with it (during the 8k walk there weren't many people there and I had my iPad with DJay playing a Spotify playlist (thank heavens for redundancy and backup plans). But after a while I just gave up. I carried my CD-case (see remark on redundancy and backup plans :-)) and finished the night playing from CDs. Couldn't use the iPad, since it was also in use as the engine for my live sound mixer (Mackie DL1608).

Two things I noticed:
1) non-powered hub. Shouldn't be the problem in my opinion, but will remedy this and do some extensive testing.
2) The power wasn't too stable and kinda fluctuated between 210-220V. I HAVE played in situations like this before (even worse with a bad and too small generator) with the 2900s just playing CDs and not had any problems. The MBP has a battery and shouldn't be too dependent on the power grid as all the adaptor does is charge the battery. The USB hub (as said) has now power, so no issue there.

Please let me know what other information I can provide to help get this fixed. As it stands I have to ban Cross from live performance in this set-up and that is not really a nice option.
I will try some more testing this week in the warehouse to see if I can reproduce things and figure out if there is specific combinations that trigger these events.

Greetinx.

Do not want to exclude any issues as described, but the power is signifcant off from the current 240V standard. Older 220-equipment might be running smooth, but newer might have some more issues, especially if downpeaks may have been even lower.
Might even be that other equipment than yours disrupts the current.

'removing' a soundcard shouldn't crash Cross. It (normally) only stops if the 'next listed' takes over, or stops is this routing is not matching. (but some changes were made to sc switch behavior).

Distorted sound not likely originates from Cross. More likely a driver issue (guess you checked latency).

While writing this (and reading your info again) my guess is that your USB hub could very well be involved here. Given the power issue it might not be a root cause but it would explain quite some of the behavior.
I've had some USB issues in the past and must say that since I have a powered hub haven't seen it no more (nor tried without).
Another thing coming to mind is USB3 vs lower USB compatibility issue...

In laptops (don't know MBP)often internal USB ports are shared, which may confuse users on limited availablity of power, especially when one hdd consumes more than max ...

RoJeC wrote:... but the power is signifcant off from the current 240V standard.

True, needs looking into on my part. Will see if I can reproduce this behaviour when on a stable power outlet.

'removing' a soundcard shouldn't crash Cross. It (normally) only stops if the 'next listed' takes over, or stops is this routing is not matching. (but some changes were made to sc switch behavior).

Again, will try to reproduce. I probably will hook it all up. Then set my camera on a tripod and run video of the things I do. I will switch off a SC2900 while it is and while it isn't playing and see what happens.

Distorted sound not likely originates from Cross. More likely a driver issue (guess you checked latency).

It being a MacBook, there are no driver issues (usually). Also latency has never been an issue. Besides, it plays songs well for a bit and then suddenly the sound goes off, while the other deck still plays with clean sound. It's really odd behaviour and I wouldn't mind if it all stems from instable power.

... my guess is that your USB hub could very well be involved here.

I HAD tested with the same USB hub the day before without any problems, so could very well be the combination of unpowered hub and power problems.

... Another thing coming to mind is USB3 vs lower USB compatibility issue...

The hub, the MBP and the SC2900s are all 2.0. So compatible should not be an issue in my opinion. As I said before, everything was tested the day before for almost two hours. The more I think about it, the more I feel it has been a power issue. If I can't reproduce the problems in the warehouse on stable 240V, we will know for sure.

... often internal USB ports are shared ...

With only two available USB ports (the most embarassing shortcoming of an MBP in my opinion), I am guessing they are on a shared internal hub. One 2.5" HD running off one port, the passive hub on the other. Even though it tested well before-hand, the power might have thrown a ratchet in the wheels.

Thanks for your reply. By the look of it I will be able to test tomorrow morning. Will keep you posted.

Greetinx.

It took a while longer than expected, but yesterday I finally managed to set up my system again.

And I can happily report that, so far (I ended up experimenting with adding an extra controller and my midi-compliant mixerand swapping around MIDI channels and such, for which I powered the hub), there has been no repeat of the trouble I had during the low-power outdoor event of 3 weeks ago.

No sound deterioration, no odd crashes and no soundcard issues.

I will continue doing some longer sets in the coming days without the extra controller and my mixer not connected to the laptop/hub and no power to the hub, but based on how fast the problems occurred (minutes to quarter of an hour tops), I am confident that the power was them main, if not only, contributor.

Since I never had these problems while playing out with my old ADJ CD-players and my MC6000 mk1, and I never used an hub in that setup, the culprit is either the 2900s that have a problem dealing with low power input and/or the (non-powered) hub.

More testing to follow, as I said. Will keep everyone posted. In the meantime I will start looking for one of those power bars, that tells you how the power is at a venue