Vocals gone missing?

[alex_kyuss]

Hi all, hope everyone had a good weekend.

 

I'll start with the details,

Soundcraft GB4, Behringer GEQ, QSC PLX, Yorkville monitors

 

I was engineering a asian music festival last week in Manchester and all went well for sound check. Halfway through the 3rd act the vocals faded out from the monitors but the guitars and percusion were still there. We swaped all the cables and swaped monitors, bothing changed. The amps stayed the same so we think they were broken! My question is has this ever happened to anyone before, were an amp has stopped working but only for vocals I can't think of any reasons for this to happen. Has anyone else?

 

Cheers all Alex

[noodle]

It couldn't be the amp for the monitors or evrything would have dropped out of the monitor. Sound slike it would have to be a desk issue.

[niall]

I would very much doubt it was the amp that was broken, given that you say that guitars and Percusion was still comign through. Fault inside the desk perhaps? Did you try puting the vocals on different chanel and sending them to the monitors?

 

edit: man I'm a slow typer...

[Rob_Beech]

Agreed, this must be at the desk for your MIX to alter. Everything after the desk deals with the complete signal only.

 

I would do some testing of the desk, some of which will be work with the lid off, so if its under warranty then after basic testing I'd advise getting it returned, and hiring another in the meantime.

 

I would have thought that what has happened here is that a pcb or part thereof or a ribbon cable has failed within the desk, and this is therefore not sending your channel(s) signal to the aux bus(es). This would mean that the group of channels associated with that cable will not be sent, whereas the other channels will.

 

You would tend to find on a "standard" layout board that the vocals would be on a different part of the desk to that of the percussion and backline, and it is this reason why only they were affected.

 

Of course it could be a different fault but this is just an educated guess.

 

Was this board solely a monitor board for the event or for FOH aswell. If it was just a monitor board, were the auxes set pre/post fade? does the channel output to the main bus?

 

 

Rob

[alex_kyuss]

Hi It was doing both FOH and monitor, but I spoke to the guy who owns the stuff after I wrote the thread last night and he says he used a completely different set up last night but with the same amps and the same thing happened. We did think it was maybe a pcb or ribbon thing but we swapped channels to a different channel group completely (not to the guitar channel though) and the same result.

Oh and the gain was being weird I turned up the gain on the vocal channel and nothing happened, until feed back (I guess this MUST be a desk thing) nothing on any of the meters until it started feeding back.

 

I hope someone is less confused then me

Cheers for your responses Alex

[MarkPAman]

............. the vocals faded out from the monitors but the guitars and percussion were still there.

 

Did they really fade out, or did they stop suddenly?

[DavidLee]

Any chance that you could accidentally have hit the phantom power button? Problem could arise by turning it on as well as off, depending upon the mics you were using.

 

David

[Rob_Beech]

Or a failure in the +48 rail if the mics DO need phantom and nothing else you happened to be using did.

 

That said, this would also effect FOH. You say that he used a different setup, but the same amps, does this mean different wedges, a different desk, different eq's etc?

 

Are you 120% sure that there was still a signal (guitars and percussion) coming from the wedges and no vocals? Was this every monitor mix or just 1 or some?

 

Also (and importantly) whilst you didn't appear to mean this in your original post can you just confirm that they were still working fine for FOH.

 

Rob

[paulears]

so the monitors were working, but the mix in them changed? If so, then discount amp problems - if some sources 'emerge' the amps are fine. So it's almost certainly a desk issue. how about looking at the channel strip that does emerge from the monitors - does adjusting the send control work? Try another desk channel and see if that works - if it does, try a mic through that one and see what happens. It could be that the send from the vocal channel is the problem - if it's a ribbon connector underneath, then maybe it's just worked a little out of the socket, and the link to the monitor bus may be intermittent. If things fade, as opposed to cutting out abruptly, then power supply/iffy caps, and dry joints may well be a cause - most likely on the vocal channel strip - that is where I'd look first if there is some monitor output.

[peternewman]

I don't do much sound, but when you say the vocals disappeared, are you sure you didn't for example loose the top end, where admittedly there would be some guitar, but not much percussion, and there would still be some of both left at lower frequencies? Probably completely wrong, but just a thought. If this was possibly the case do you bi-amp and have you tested that side of things?

 

Also do the failures occur say 20 minutes into the show, or another similar time period, in which case is something overheating?

[The Boogie Man]

We'll assume the mics, leads and anything else before the desk has been checked?

[RustyBrooks]

The most common cause of fading signal down to a negliable level, or silence, is a broken capsual in the mic itself, somtimes if one is broken by water ingress, then a whole batch maybe, so a wet vocal mic, could be indicative of lots of wet vocal mics. Desks tend to fail, in my experience, with a catastrophic bang (power supply, if your stupid enough to only run one, or dc failure), or intermitent crackles/signal (pcb/ribbon). Put a pint at london prices on the microphones

[Jivemaster]

If the vocal went from all places then it's most likely a mic problem. If the vocal went from some places its a desk/finger problem.

 

Cables test out easily, mics not so easy but a dynamic mic is about 150ohms dead short indicates the switch is off! over 1K indicates a failed mic. --only holds for dynamic mics tho.

 

Yjen start with one proven good mic and plug it in each socket and see if there is a routing failure - not getting to one output from one input.

[alex_kyuss]

Hi all.

 

Ok

1. According to the band the vocals faded out quickly.

2. there were no mics that used phantom power.

3. nothing went wrong with FOH, all went well.

4. someone else used the same desk the night after and he had no problems

5. on the night we swapped everything other then the desk and the multicore

6. the vocal mics changed from wired sm58 to wirless 58 same thing with both and back again through the night

7. there was no crackle / pops just loss of signal

8. I ran up to listen to the monitors and listened them and they sounded fine other then no vocals, guitars and drums all sounded fine.

9. im going to check that mixer next monday so I'll be able to go through it myself and if I find anything I'll tell everyone.

but it has been used since with no problems so a loose ribbon / pcb seems quiet possible.

10. monitors only use a single amp.

 

I think I've covered everything people have ask but if I havn't just ask please

cheers all

ALex

[Rob_Beech]

So we've eliminated microphones from this then. Twas a good idea though had they faded from FOH aswell, with the liquid etc.

 

We've also eliminated the leads as they can't alter the mix, nor can the amps or the monitors themselves.

 

So if what you say is correct, then it has to be the desk, as this is the only device in the chain to mix the signals. Probably best to get it looked at as soon as you can.

 

Again, I'm sure if you need to hire one in the mean time someone here can help.