Intermittant Static Bursts - QU16

Qu Qu Troubleshooting
1

Greetings All

We run a QU16 with an AB168 stage box. Speakers are 2 EV112P’s and 2 EV118P’s. Stage monitors are one or two AltoTS112a and 2 sets of stereo, Sennheiser and Nady IEMS.

At a recent gig, we were plagued with intermittent bursts of static.

An example of is here, recorded off a Zoom4 camera. That was the actual sound coming through the PA, as picked up by the camera mic. It may or may not have been coming thru the monitors. Not sure.

We turned off all the wireless equipment, (IEMs, wireless mics, wireless guitars) and that did nothing.

There was nothing showing up on the board that I could see to indicate where it was coming from.

Eventually, I noticed that it occurred when our female vocalist started singing into her wired mic, but not always. We changed mics out, but the problem reoccurred, suggesting it was a bad XLR from the mic direct to the QU16. I muted the channel, (Ch2), and the problem disappeared.

What is strange is that I recorded most of the show in 16 tracks on the QDrive, (until pulling that off line + the ST3 MP3 player to ensure that wasn’t the issue). On the playback the next day, though the static can be heard on the Zoom4 video recording, it is not heard on any of the tracks recorded thru the QDrive and there is no evidence of an anomaly on any meters I can see.

It may just be a bad XLR, but even so, wouldn’t that have registered on the multi track recording as well as via the FoH speakers?

And why would this only show up on the FoH speakers?

It was not a good situation and certainly one that does not need to be repeated. Is there anyway I could have quickly isolated the issue given the intermittent circumstances?

Does anyone have any ideas or suggestions as to what the issue might have been?

Note that we had to switch out the AB168 at the last minute because the QU16 wasn’t seeing the stage box, but was sending QU drive 16 track recordings to the FoH, with no ability to control volume. We relocated the Desk to the stage, and connected XLR’s directly, and used the IPAD app to control sound from the back of the house. But that’s a whole different issue covered in another thread…

As can be imagined, though we pulled off the gig, it was far more stress than should reasonably occur, given the equipment we operate.

Thx

2

St3 has been known to pick up interference from USB drives.

Static can be timed to the USB light going on. Normally something plugged into ST3 is enough to stop it, but not always.

I guess st3 wasn’t in the multitrack, but should be heard on the L&R, assuming they were recorded…

3

Were you using an iPad for the Qu-pad app? If so, what router/WAP and how have you set up your network?

Since it appears to be channel specific, one would suspect something upstream from the mixer…but no smoking gun on the track makes one wonder. It would seem that something coincidental was occurring…so hard to pinpoint the anomaly unless you can get it to recur.

What else is going on in the venue power-wise and in the Wi-fi and RF spectra?

4

I’ve noticed the ST3 and QU Drive buzz periodically. It’s not great but not a deal killer.

I unplugged both the ST3 MP3 player and the QDrive that was recording the show to eliminate them as possibilities.

We also shut down the router, (unplugged it), and the Ipad was turned off. When the static bursts continued, I plugged back in to regain remote access to the board.

I used the Ipad Qu-pad app with our own Apple private network - see pic - bottom of the cabinet.

Didn’t check the RF spectra…that’s beyond me.

There were a lot of power bars on stage. I’d like to see the band pay more attention to what should be plugged in directly to the mains and what can easily be channeled thru extensions and power bars. You know what it’s like when everyone is independently setting up their stage gear. It’s like herding cats…

5

Hello,

I started to notice same problem on my QU24 described as “STATIC BURST”
Is there any clue what this sound is,what is producing it and most important:how to get this issue SOLVED?

6

I’ve got the exact same problem with my Qu-Pac. Bought it last May. I used a Qu-24 last winter and last year the exact same problem. ut it was a sound desk used by many different bands so I thought it was a bit damaged. We already noticed with my band at the time it was doing it when we were singing loudly in our mics.
And now it’s doing the exact same static burst (really loud!) on my Qu-Pac. I did some multi-tracks recordings with the Qu-24 noticing the burst was in multiple tracks, not only the mic track that made the burst appear.
I’ve tried updating the mixer but it doesn’t change anything. It needs to have a lot of sounds to appear. I’ve tried at home with just a mic and it doesn’t do it. The only way to avoid most of it is to reduce the gains on the mics… but it’s not really a solution…
can anyone help?

7

could it be a distorting FX engine?

8

Wasn’t doing it on tracks with FX so I doubt it. And it’s REALLY loud.

9

it still sounds as an internal clipping to me, maybe a reverb or maybe the master bus (pre fader)
how are your speakers connected?
wich processing is activated in the channels?
the recording is normally pre processing, so if it is not on the recording it has to be after the pick up point of the recording

10

So.
Thanks for answering.
I use all the time a reverb as FX1, sometimes I add a slap back delay on FX2 and regular delay on FX4. But the burst occurs intermittently wether the FX2 or FX4 are activated or not.
I use compressions on the vocals as well.
The noise burst occurs on many channels, using FX or not, compression or not, in the recording as well, on many channels as well like I said, but not all of them.
I’ve got three monitors on outputs 1, 2 and 3, an ear monitor on outputs 9/10 and of course the main speakers on the main output.
I would say we can hear it everywhere but since it’s really loud, I can’t say for sure. Sometimes I use ear monitors on outputs 5/6 I think it wasn’t in it since it wasn’t as loud as in the speakers…

11

so… is it in the recording or not?

12

your microphones will pick up the noise too, only your line signals will be clean
and the microphones will pick up the noise in different volumes, that depends on the position in the room

hire a technician to find your problem, it’s not that easy from here to say where it’s coming from

13

@Aykoma
I think you got a different problem…