An SQ-7 I was using experienced a forced shutdown and reboot.
This occurred during a rehearsal.
A performer had brought an amplifier onto the stage and was sending a line output to the PA system via a DI box. They were using an acoustic guitar and a wireless head unit (I didn’t verify the frequency, but it appeared to be a 2.4GHz system).
Loud feedback—resembling interference from an analog wireless system—occurred, and the SQ-7 shut down.
Regarding the situation, I suspect the following factors:
① The cable connecting the network port to the wireless router was a standard UTP cable.
② I was performing multitrack recording to an SSD that was not self-powered (bus-powered).
As countermeasures, I am considering:
① Switching to an STP cable.
② Discontinuing multitrack recording or using a self-powered SSD.
Please let me know if there are any other potential causes or countermeasures.
Power was supplied by a 2.8kVA inverter generator.
No UPS or power conditioner was used.
*Note: For the actual performance, I had the performer switch the wireless microphone they brought to a wired microphone on a separate channel, and there were no issues.
As this text has been converted from multiple languages, there may be parts where the meaning is awkward.
Thank you for reading.
You said the event went on fine when you switched to a wired mic and another channel on the console. The quickest way to see if the issue was caused by the wireless system or was actually feedback caused by a routing problem in the console else is to plug the working wired mic into the input that the wireless system was plugged into. If you get the same loud feedback with the wired mic, then you know it is a feedback loop created in your audio routing for that channel.
If it turns out to be feedback and not a problem with the wireless system, I suggest you start looking by checking the vocal FX routing. It is pretty easy to use a group/aux buss to send multiple vocal channels to the same reverb or delay FX rack, and then accidentally add that reverb/delay return buss into that same group because you want the reverb/delay volume to change with the vocal group level. This actually causes the FX sends to be looped and will cause immediate loud feedback. It’s possible that the wireless mic channel was routed into a vocal group like this, but the wired mic channel wasn’t routed the same way and therefore didn’t cause any feedback.
However that feedback occurred, I simply cannot imagine it causing the console to shut down and reboot.
(The opposite is more likely: feedback caused by the mixer is booting up.)
Unless there is a hardware fault in the desk itself, this feels for me much more like a power supply issue with your generator - such as a brief power interruption.
Is it perhaps a run-of-the-mill unit intended for lighting and hotplates, or is it a higher-quality device capable of powering sensitive electronics?
And is it suitable for your specific hot climatic conditions?
I cannot vouch for the quality, but since it is an inverter generator, I assume it outputs a pure sine wave.
The temperature at the time was between 25°C and 30°C, and it was cloudy.
Only the SQ-7 shut down; the other devices—including the amplifier—did not lose power.
I have heard from colleagues that shutdowns can occur during multi-track recording.
I wasn’t referring to the quality of the sine wave itself, but rather to potential short interruptions.
A key factor might be that your other devices don’t have a boot-up process at all, only the mixing console does.
So, are you assuming that the cause wasn’t the feedback, but rather a multitrack recording?
I’ve never heard of or experienced either scenario, and you should definitely report this to A&H support.
This user forum islikely not the right place for that kind of issue.
Biggest question is, what else was on the generator ?
Was the PA powered by the same generator ?
And what size of PA are we talking about ?
The sine is not really important for the SQ, it has a switch mode power supply. 2.8kVA is nice for FoH and the stage, but nothing if you have heavy class A/B amps with no power factor correction. And 2.8kVA is what the generator is supposed to be able to give, not what it really does, it strongly depends on relative humidity, temperature, altitude, regulator calibration, carburation, aging etc…
If the PA is powered by the same generator, a possible scenario could be:
→ you receive a big interference in the wireless 2.4GHz receptor
OR you make a routing mistake like Brian-1 suggested.
→ LOUD NOISE !!! The PA now pulls lots of power
→ generator almost stall
→ SQ brownouts and shuts down
→ Sound is cut, power demand falls to zero, generator recovers
→ SQ restarts, you mute all and you’re now looking for the issue
If the issue was routing, be aware that the SQ will not save the latest changed parameters straight when you touch them. They are written in non volatile memory only after a few seconds. The routing mistake is likely gone after reboot if the shutdown happened quickly.
You didn’t had the power issue after because you likely never asked that much continuous power from the PA after the incident.
Alright, long post. It’s only theory, but it’s the only way I see this could happen, more or less.
Good luck