Monitor Desk Wiring

[buck_rogers999]

Hello there,

 

was just wandering if anyone knows how best to wire a patch box if you want to do monitors with an LS9 and send a signal FOH to an M7CL as they dont have direct outs (is it just a case of making up a patch box with one input two outs basically a Y split internal)

 

If so what happens about phantom power do both desks have to have it on with condeser mics or just the one desk?

 

Have also thought about connecting the desks via ethernet but want to ahve 48 channels going into the LS9 and then direct them out down an Etherent Cable to the M7CL FOH does anyone know if that is possible as I would already be taking up one card slot for 16 more XLR inputs and therefore want to find a card I can put in both desks so I can then run 48 channels FOH and then just two XLR's for Left and Right.

 

Any help much appreciated.

 

Matt

[StevieR]

Monitor splits are normally achieved at the stage-box with separate wiring going to both FOH and monitor desks. The split can be done using a simple Y-split but this can result in problems. The more professional systems use either isolating transformers or active circuits to split the signal.

 

For phantom issues, only one desk should supply this - a decision between the FOH and Monitor engineer. Some transformer based splits may not transfer phantom on certain outputs and may affect the decision here.

 

Steve

[Rob_Beech]

Agreed, always supply phantom from 1 desk only. Whilst most of the time it shouldn't make a difference it has been known to cause big problems if you supply from both. A direct passive output from the input is required to allow phantom power to go through, although most active splitters will have phantom available from them.

A splitter is certainly the best way to do this, using outputs from the monitor desk will mean that your input gain control in monitor world will also control the level at FOH, this is not what you want and kind of defeats the object somewhat.

 

Rob

[buck_rogers999]

Hi there thanks for the help.

 

Do you know where I can get these active splitters from to wire into the Stage box?

 

Also if I didnt go down this route what sort of problems would I encounter if I was just to simply Y-split the signal.

 

Thanks

Matt

[Ben Langfeld]

A decent unit to get your hands on would be the KT DN1248, though you should expect a rack of these to out-price your desk. A cheaper alternative would be the Thomann T-Racks MSP124, though I have never used these and could not comment on their performance. In many cases you will get away with simple Y-Splits, or if not, transformer splits. Rarely is an active splitter actually required.

[paulears]

There's some useful stuff here.

[Pete McCrea]

Most of the companies I know manage with passive splits built into the stage box system. The stage box will usually have the XLR input, with then several Multi-pin outlets, allowing a feed to FOH, one to Monitors and potentially a third to OB. This is generally done by wiring three cables to each XLR or Multi-pin connector in parallel. This seems to work fine in most circumstances, and as mentioned by others the FOH guy and Monitor guy take the call as to which end Phantom is from.

[Andrew B.]

I know a small company in Exeter called "Orchid Electronics" that makes high quality audio products of this kind - we use many of their DI boxes and I have been in discussions with various churches who use custom-made headphone monitoring systems made by the company, which are apparently very good. It is run by a chap called John Godsland. If you look down the home page you will see details of their mic splitter system - it's a passive system with one set of transformer isolated outputs and a second set of outputs that can send phantom power to the inputs. He can custom make it into walls or stage boxes.

 

Orchid Electronics UK

 

£210 inc VAT for 8 channels in a 2U rack, which seems like reasonable value, given that their products appear to be robust and well-constructed/designed. He also supplies custom cables very cheaply, if you are feeling too lazy to make up your own.

 

Andrew

[mervaka]

the allen & heath monitor desks such as the GL2800M have splits built into the back of the desk, and of course achieve everything you'd expect on a splitter box. of course you've already got a couple of digital desks, so I doubt this is an option for you.