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Codemonkey 11 December 2007

Hi guys. Nothing major, apart from the lack of equipment and budget, but it's a Church so that figures. Just a rant about the new sound system. Our old speakers mounted on the walls (removable but bloody awkward). 24 x multicore with 4 returns underground, 2 speaker cables and a VGA lead for the projector.
Sounddesk has an amp in it which is either 100, 300 or 500W but the speakers are "200W Continuous 400W Program" so I put the amp to 300W. Couple of stage monitors which are 150W Continuous/300W Program and these are attached to a stage-side 100W amp. 3 returns are in use, one for a induction loop system (a separate, 5-year old 100W amp for this) and 2 for stage monitors going into the amp.

Unfortunately there's a fair amount of buzzing somewhere in the mid-range as soon as any instrument has the gain put up much, and the projector has bars which seem to be coordinated with the sound interference. We use a radio mike for the Minister but everything else is wired. Buzzing happens anywhere, is there anything to do about this?

Also, if anyone else mixes for a Church band, how do you compensate for the congregation drowning out the band? Drop the vocals, enhance the guitars etc?
Which reminds me, the speakers are quite quiet. Should I put the FoH amp back up to 500W, or just increase the pre-gain (faders are set to 0-ish) because the stage monitors are too quiet now, although increasing gain increases this buzzing?

Sorry for badly ordered post, but the system is badly assembled so it rubs on me :) seriously though, it's amateur. And what really bugs me is that I can't get the loop volume set right and all the people I ask about it, either have new hearing aids or forgot them!

Comments

Codemonkey Tue, 12/11/2007 - 18:22

2 FoH speakers, one on each channel on the board's amp. 2 stage monitors coming from independent returns. Nothing wired in parallel. Everything is run down a 20m multicore to the mixer, then back up various cables to the stage.
Sorry, but being far from expert, I dunno what a wedge is. Other than something to hold the floorboards apart...

Underpowered? Well it probably is. The stage monitors are for sure, the amp is (I think) 90W (~300W speaker). Doesn't help, I've gotten into a habit of keeping the Aux volume low because the old system ran off the board's 300W amp.
The hall is about 20m long and 8m wide with pillars down either side. The speakers are too high, the drummer is kinda loud, badly isolated and the whole system sounds rotten.

I guess this is just one bad setup and everyone here can probably name a worse one. How do you work with it?
Should I put the mixer's amp back up to 500W to drive the FoH speakers better? Or just increase the channel gains (and pick up buzzing) and therefore increase the monitor levels.

Don't you hate it though, when you have to work systems with no extras like compressors? I'm using £10 headphones ($17), which is how bad it is.

bent Tue, 12/11/2007 - 20:50

Underpowered? Well it probably is. The stage monitors are for sure, the amp is (I think) 90W (~300W speaker).

Should I put the mixer's amp back up to 500W to drive the FoH speakers better? Or just increase the channel gains (and pick up buzzing) and therefore increase the monitor levels.

Stage Monitor = Monitor Wedge (they are typically wedge shaped). They are way underpowered, so are the mains.

Switch the mixer back up to 500 (it's ok to overpower >most< cabinets upwards of 30%, I hit my ARCS and SB218s a lot harder), talk to someone about getting a new monitor amp(s), and make sure you're hitting your inputs at unity.

Have you tried any IL19 transformers on the buzzing lines?
http://www.whirlwindusa.com/spcint.html#il19

Try moving the VGA lead away from the cables, that might be causing some of the buzz.

Codemonkey Wed, 12/12/2007 - 10:17

No can do on the VGA cable. Wasn't me that put them under the floor and I've no idea where the hole is or if they even left one.
The Church itself is full of odd buzzing, when we rigged a system up in one of the halls, I found that I could get a fairly good radio signal from one of the mikes. Thankfully that mike wasn't needed though.

Thanks for the advice about the amp(s)/cabinets.

Codemonkey Wed, 12/12/2007 - 11:20

"The church's power might be the culprit with the buzzing."

Well, the electrics are probably the 1933 originals. I've been told it's actually near-capacity (near enough to not be able to power some ceiling fans). Although, the heating is probably to blame. There's an 8m electric bar under each of the 18 pews.

"Do you know where the ground is for the building?"

Underneath. :P I'd imagine it's still hooked up because nothing is majorly malfunctioning. Honestly though, I don't know. The lighting/electrics are a mess. Come to think of it, one of the switch boxes was buzzing audibly last time I was there.

I'll get someone to take a look at the electrics.

Codemonkey Fri, 12/14/2007 - 16:04

Well, I asked the minister. He says someone checked it 2 years ago and it was totally fine, and that that specific box buzzes whenever the heating is on. Can't say I've heard it before, although I'm never really near it for long enough.

Also, just thinking about the grounding wires...this is the UK, with 3 pin plugs. Dunno if that changes your line of thought? Not that I paid attention to the plugs while on holiday in the US but I'm assuming a separate grounding system is required? If so then it's probably not the problem.

Codemonkey Fri, 12/14/2007 - 16:55

3 pin plugs are Live/Neutral/Earth so yeah (there's a funny rhyme about wiring plugs that escapes me) I would assume a common ground is used but I'm unsure.

Never used the mixer when the heat was off. If I have, it was before the system went in properly, and then we had a snake that we ran down the side of the hall.
It's not as though the sound buzzing is a major problem, it's just something I noticed when I put the gain up a fair bit. Beyond what would be needed for a single singer on a mike, but if we try a choir-setup it'll come back and haunt me for sure.

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