Mic level patching

[revbobuk]

So (see other thread...) we're planning on re-doing our church platform. And I've planned floor boxes and connection points to give me more places to plug stuff in than I need, to allow flexibility. 40, in fact. But the mixer won't handle that, and the multicore going back to the mixer is only 16 ways. And we don't need any more than 16 channels anyway at one time.

 

And I was planning to use a patch bay, so that I could have a default set of connections made, and then use jumper cables to patch different sockets to the multicore channels when I need them.

 

But I notice in one patchbay's manual that they do not advise use on mic level circuits. So what is the right way to do this, if I can't use a patchbay? And why would a decent patchbay be a worse thing to do than a DIY patching system using XLR connectors? Any words of wisdom for me?

[Shez]

The only reason that mics on patchbays can be problematic is the presence of phantom power which can be shorted by plugging and unplugging the jacks. This can generate quite loud pops. Assuming that you'll never be plugging live circuits, I wouldn't think you'd have a problem.

 

My biggest venue has facilities panels all over the place which all come down to one central amp room where all the patching is done - XLR connections are all patched on one big bantam patchbay. These can be line level or mic and are usually set up before the mics are even plugged in so it's never been a problem. Make a habit of doing all your patching before plugging in anything else and you should be fine.

[paulears]

There's no real problem with using patchbays at mic level, IF you keep up the maintenance. I had a studio where all the mic lines in the recording area could be repatched to the big recital room next door. The problem is just a bit of occasional noise due mainly to the normalling introducing lots more contact points - but every few weeks we used one of those hollow abrasive jacks - Canford Audio was the source, I seem to remember - you stick them in the jack, stick the switch cleaner tube down the hole, and then squirt and spin them a turn or two. I've also heard people say that the problem is worse due to phantom power - but I never had a problem with this.

 

I'd certainly do it again - the problems were very rare really and the flexibility easily made up for a bit of extra cleaning. The less contact prone solution would be an XLR patch, but the Re-an ones we used with the reversible cards and standard not bantam jacks worked fine.

[djw1981]

We have something similar - 6 stage boxes, each with 6 Mic inputs, 2 jack inputs, 2 bNC and 2 XLR returns.

 

These are labelled A1-F12 in the patch bay then we use a loom labelled Desk 1-Desk 12 to go up to the desk. Other local inputs are on a seperate loom.

 

So my Patch plan looks like

 

AC Guitar - channel 11 - Desk 3 - A2

 

Vox foldback - Aux 3 - Desk 12 - F11

[bassnote]

I would tend to go away from jack patch bays for this and do a custom XLR patch.

 

some bits I did this before with was:

 

50cm XLR leads are £1.59

http://cpc.farnell.com/rean/nra-000-0330-0...0-5m/dp/AV18029

 

16 hole rack £7.11

http://cpc.farnell.com/_/r1269-1uk-16/pre-...002?Ntt=EN81002

 

Peter

[Paul TC]

Method used at my church (before I arrived), is to bring multicore to Stage Left with stage box screwed on wall and then bring back the circuits from remote points as flying leads terminated in XLR plugs and we then patch as required.

Slightly neater would have been to put them in a box and gland them out rather than a lot of wires with last cable clip holding them.

[stevefez]

Method used at my church (before I arrived), is to bring multicore to Stage Left with stage box screwed on wall and then bring back the circuits from remote points as flying leads terminated in XLR plugs and we then patch as required.

Slightly neater would have been to put them in a box and gland them out rather than a lot of wires with last cable clip holding them.

Indeed that is the system currently used in my church. It's next on the 'upgrade' list. Right after replacing all the floor boxes as well, as it happens.

[Solstace]

We're about to rip out our "Type B" patchbay in the coming months. Why? Because despite its ease of use and it functioning correctly as designed, when used by humans it's the least reliable part of our system. Contacts get dirty, people forget to insert/remove patch cables as necessary, and commonly if someone nudges a cable while the sound system is on, we get nasty pops and bangs if said cable happens to be carrying live audio with phantom power. Or worse still it has been known for someone to nick all the patch cables as a jolly jape... and oh nuts - no sound system that night. Woo.

 

For theatre and other venues where you can have the patchbay in a locked room that's not used by anyone other than the sound guys, a patchbay can be a really useful tool. But in a church? Honestly? Take Paul TC's method or go with a larger desk where you can dedicate channels to specific tasks.

[revbobuk]

We're about to rip out our "Type B" patchbay in the coming months. Why? Because despite its ease of use and it functioning correctly as designed, when used by humans it's the least reliable part of our system. Contacts get dirty, people forget to insert/remove patch cables as necessary, and commonly if someone nudges a cable while the sound system is on, we get nasty pops and bangs if said cable happens to be carrying live audio with phantom power. Or worse still it has been known for someone to nick all the patch cables as a jolly jape... and oh nuts - no sound system that night. Woo.

 

For theatre and other venues where you can have the patchbay in a locked room that's not used by anyone other than the sound guys, a patchbay can be a really useful tool. But in a church? Honestly? Take Paul TC's method or go with a larger desk where you can dedicate channels to specific tasks.

 

New desk isn't an option - we'd be looking at a GL2400 as a minimum, and we don't have funds for that. And the issue with cabling back to the multicore stagebox is that you end up with a mess of cables, no matter how tidy you try to be - that's what we do at present. But I take your point about unpredictable people - I think we'll probably go with an XLR patchbay we construct ourselves, using populated 2U/24 way panels from CPC.

 

And our desk is plenty big enough - the issue is rather that for one service the flute player might be SL, next week she might prefer to be SR; one service we have one mic for vocals, and she stands next to the keyboard, and no other instruments are playing, but earlier that day we had a full 7-piece band with three vocalists. So we need the flexibility!

 

Really useful comments so far - thanks folks.

[Andrew C]

There was (may still be) a glut of second hand patch panels on the market. I've installed several over the alst 15 years or so and seldom had any problems at all, and all of those have been down to errors in the wiring. Hmm... better go and fix that soon!

[ajh51]

The band changing week-to-week makes a flexible patch system very handy in a church. Also people generally are less tollerant of lots of wires on "stage" because there is a lot more traffic from "unskilled" people; clergy, congregation members etc.

 

We have 6 stage boxes with both XLR inputs and speakon outputs so the cabling for each musicians mic/instrument and monitor can be short and neat.

 

The inputs from the 6 multicores from the stage boxes come to a patch panel at the side of the stage . These are just terminated as XLR tails (exactly as PaulTC's suggestion of glanded outputs) and labeled to match their stage boxes - we use numbers and colours.

 

The inputs to the desk are then made to female panel sockets 1 per desk channel and labeled clearly as "desk ch 1-48" (in our case).

 

This way there are no short patch leads to go missing and any one who has used a "normal" multicore and "normal" desk can get their head around what is happening. We have a patch sheets made up to help the sound team and these are laid out in the "correct" order and lead our guys through the setup working from stage to desk, following the signal. Therefore they will generally not turn on the amps until the patch is made avoiding pops and bangs.

 

We use the same system in reverse for the 4 channels of monitors we run from FOH. Each monitor amplifier output is extended from the amp room to a speakon tail at the patch panel beside the stage and each stage box also has 2 speakons which terminate at the patch panel as sockets.

 

It has been in for 2 years, is re-patched at least 4 times/per week and there have been no problems thus far. In fact it works very well.

 

I can try and take some pics if it's not clear - feel free to PM me.

 

Andy

[Bobbsy]

I have to say that, in the TV industry, we used to have racks and racks of huge B-gauge/GPO patchfields and rarely had any significant problems. We used to occasionally run a "burnishing tool" through the lot just to be safe but that was about it. I'd wager that the audio for every TV programme you watch has run through multiple patch fields.

 

For mic level sources, the one thing we used to do was keep those strips separate and isolated from line level stuff. Whether this was truly necessary or just my paranoia, I don't know--but we never had any problems.

 

Bob

[Stan Hope-Streeter]

I have to say that, in the TV industry, we used to have racks and racks of huge B-gauge/GPO patchfields and rarely had any significant problems. We used to occasionally run a burnishing tool through the lot just to be safe but that was about it. I'd wager that the audio for every TV programme you watch has run through multiple patch fields.

For mic level sources, the one thing we used to do was keep those strips separate and isolated from line level stuff. Whether this was truly necessary or just my paranoia, I don't know--but we never had any problems./>Bob<

 

I was taught always to give the plug a half turn each way after plugging in, to help clean the contacts.

And yes the occasional use of a burnishing plug is very useful especially on jackfields that aren't in constant use.

[revbobuk]

We have 6 stage boxes with both XLR inputs and speakon outputs so the cabling for each musicians mic/instrument and monitor can be short and neat.

 

I can try and take some pics if it's not clear - feel free to PM me.

 

Andy

 

Would love to see some pix if you have time - sounds just like what we are trying to do.

[MarkPAman]

We have a system which is, I think, the other way arround from most.

 

Our studio has something like 80 mic inputs coming from 5 different rooms (3 are part of the studio, one is a large reheasal space and on is our recital room in another building). These all emerge as (male) XLRs in pannels in a rack. The multicore to the desk is then (female) tails, so you plug No1 from the desk into whichever XLR has your number one microphone & so on.

 

So instead if 80 tails that can go into 24 sockets, we have 24 tails that take signal out of 80 fixed plugs. A slightly neater solution I think.