Urgent Problem - i am recording a brass band concert with audio and video - big thing for me, 32 Channels of Audio and 12 Cameras. I own my Sq-6 for many years, have made many many successful recordings. Since today i have the problem, that all signals from my 2 DX-168 stage boxes sound terrible rattling, distorted, unusable. As well live, when i am listening PFL the single channels, as on the recording. Only the local connected Ambience Mics are sounding clean and ok. Sampling Rate is at 48KHZ, Clock is at internal with a green hook symbol. What would you do, what would you check. I have already changed the CAT Cable und tried also to connect only one stage box - it makes no difference. Latest firmware is installed! I have tomorrow on Sunday a second and last chance for recording. Please listen to it: Stream Leopold Denk | Listen to Allen Heath SQ6 Problem playlist online for free on SoundCloud
And is this really the case on every single one of the 32 DX168 channels?
It sounds like everything is overlaid/modulated by a hum (mains frequency?).
Are there possibly completely separate mains power connections for electrical devices with grounding contacts that have something to do with audio?
Thanks fĂĽr the reply! Yes its on every sinlge channel, even when i listen Solo PFL. The strange thing is, that it worked fĂĽr 15-30 Minutes. I also think, that it has something to do with POWER. We will check this in the venue!
Strange. So there’s no difference between mics with/without Phantom Power supply?
Otherwise it could be a faulty mic/cable/phantom power adapter of a clip mich that overloads the whole 48v supply? Pure speculation as both Stageboxes show that problem however.
good luck!
no difference, i have a mixed setup between dynamic and condenser mics
Which clock is at 48? The SQ and the DX are always on 96kHz.
It sounds like a not working/not synced audio driver or sample rate converter.
But that wouldn’t be audible in the PAFL. 
I hope you can/were able to sort this out.
It wouldn’t be the first venue to experience general power problems - especially if it’s not a permanent location.
He mentioned a “Sampling Rate” at 48 kHz, and he’s most likely referring to the USB sample rate.
SOLVED! The solution was, to use another power ciruit - everything was fine today, without changing any setting on the sq. I learned a lot since yesterday 
This could be a good use case for a UPS or actual power conditioner.
Did the venue use three phase power?
You can find that different parts of the venue use different phases of the mains supply.
We have three phase at our Church and we have installed dedicated A/V supplies for our equipment - stage based and A/V area.
If you don’t do this, at best you get noise. At worst, you could have a safety issue.
Dave