Control Room Cable Termination

len-morgan · Post by **len-morgan** » Fri Oct 21, 2005 12:44 am

Hello,

I'm in the process of building my studio and I've got a question about the connectors I should use in my control room's patch bay.

I've got three separate rooms (drum booth, vocal booth, and main recording room). The main room will have at least two connection boxes at opposite ends of the room so we won't have a tripping hazzard.

The connectors in the various rooms are going to be XLRs and TRS. I have some pre-punched rack panels for the XLRs and was planning on using off the shelf patch bays (i.e., Behringer PX3000) for the TRSs (guitars in, head phones out, etc).

My question is: At the other end of these cables in the studio, can/should I use all TRS connectors in a big patch bay or should I terminate the XLRs in XLRs? My mixer will only take XLR inputs at mic levels (TRS inputs are at line levels). Do I lose anything by going XLR (room) -> TRS (control room) then XLR into the mixer? I hate the idea of pluging in and out XLRs into the patch bay and if I had everything terminated at one patch bay with TRSs, I would only need one type of patch cable.

I do realize that using off-the-shelf patch panels to make up my patch bay means that I will have to solder on connectors to the end of the snake cables but it seems I would have a lot of flexibility.

Any comments?

len

Post by **Aaronw** » Fri Oct 21, 2005 4:00 am

First question. Are you planning to run your Mic lines through a patchbay? If you don't use a lot of outboard mic pre's, just go direct from the tracking rooms w/ a snake (xlr's on panel in Live room), and XLR's on the other end, plugged straight into the console.

Second: All of your line inputs, inserts, etc. wire them to a patchbay.

Third: Any reason your using 1/4" patchbay vs. TT patchbay?

Also, Neutrik makes combo panel mount jacks that are both XLR & TRS connections w/ separate pins for both types of connections. Just FYI...

len-morgan · Post by **len-morgan** » Fri Oct 21, 2005 9:26 pm

Aaronw wrote:just go direct from the tracking rooms w/ a snake (xlr's on panel in Live room), and XLR's on the other end, plugged straight into the console.

I had thought about this but I'm going to have a lot more jacks than I'll have inputs to my mixer. If you look at my studio layout (second posting), you can see I've got two rather large rooms and a nice big vocal booth. The room on the East side is going to be the drum booth (mostly) so depending on how I want to mic the drums, I could use up to 8 mics just for that. The big studio room is going to have a patch panel on on the North wall (next to the control room) and one on the South East wall (opposite corner) with at least 8 XLRs on each and the vocal booth will have 4 XLRs so we are already at 28 inputs to my 24 channel mixer and we haven't hooked up a single guitar or keyboard yet.

Aaronw wrote: Neutrik makes combo panel mount jacks that are both XLR & TRS connections

I did know about these but they are actually more expensive than buying two connectors.

Aaronw wrote: Any reason your using 1/4" patchbay vs. TT patchbay

What is the difference? Aren't the TT jacks the old (mono) jacks that telephone switchboard operators used to use? Is there an advantage to them? Are they as cost effective as 1/4" or better?

My main reason for going with standard 1/4" patch bays is that I can get a 24 channel TRS rack mounted patch bay for $40 or $50. Granted I'll have to solder connectors to the ends of the snake cables and THEN plug those into to back of the patch bay but TRS jacks (or is it plugs) are cheap and I'd have to solder to the back of the connector panel anyway.

Thanks your comments/questions!

len

AVare · Post by **AVare** » Sat Oct 22, 2005 12:43 am

The room on the East side is going to be the drum booth (mostly) so depending on how I want to mic the drums, I could use up to 8 mics just for that. The big studio room is going to have a patch panel on on the North wall (next to the control room) and one on the South East wall (opposite corner) with at least 8 XLRs on each and the vocal booth will have 4 XLRs so we are already at 28 inputs to my 24 channel mixer and we haven't hooked up a single guitar or keyboard yet.

If or the engineer(s) are competent and can count, run the mic panles in parallel, making sure to low capacitance cable to satisfy semi-techies concerned about hf loss. All you have to do is remember is to plug only one mic per channel!

I am surprised at how rarely I see this wiring method mentioned in amateur studio wiring. I first learned this method from Sounds Interchange, a studio in Toronto designed and built by some California guy called Tom Hidley. He has done a few other studios as well. (I'll now duck for cover

).

Andre

Post by **Aaronw** » Sat Oct 22, 2005 3:25 am

What is the difference? Aren't the TT jacks the old (mono) jacks that telephone switchboard operators used to use? Is there an advantage to them? Are they as cost effective as 1/4" or better?

TT's are actually balanced (TRS). TT stands for "Tiny Telephone" (if I remember correctly). So yes, this is similar to what the old switchboard operators used.

The advantage is, you can have twice the connections in the same foot print as 1/4". But, they are more expensive...considerably, but I feel it's worth it.

I had thought about this but I'm going to have a lot more jacks than I'll have inputs to my mixer. If you look at my studio layout (second posting), you can see I've got two rather large rooms and a nice big vocal booth. The room on the East side is going to be the drum booth (mostly) so depending on how I want to mic the drums, I could use up to 8 mics just for that. The big studio room is going to have a patch panel on on the North wall (next to the control room) and one on the South East wall (opposite corner) with at least 8 XLRs on each and the vocal booth will have 4 XLRs so we are already at 28 inputs to my 24 channel mixer and we haven't hooked up a single guitar or keyboard yet.

OK, bring all the mic lines to the patchbay (top row), normal the first 24 inputs on the bay going to the mic inputs on the console. Denormal the remaining inputs on the top row as well or you can normal them to other outboard pre's you may have. If you don't have other pre's, leave them denormalled, and you can use the bottom row as your 1/4" lines coming in from the tracking rooms, and patch where ever they need to go.

Your second patchbay, depending on what layout you want, can be either the insert send/return bay, or your line inputs to the console, or other in/outputs for 24 track machine, etc.

Post by **gullfo** » Thu Oct 27, 2005 4:39 am

just keep in mind that if you're using phantom power to microphones, you want to be sure its switched off before plugging and unplugging... using XLR patch is probably more forgiving this regard because you're not dragging the plug across the connections inside the patch panel... one trick is to put a flip panel in front of the patch for the mic/preamps that act as a reminder to turn off phantom power for inserting or removing connections. I generally keep my pp normalized to a set of preamps and the output of those normalized into my mixer so switching around is minimized.

Post by **Aaronw** » Sat Oct 29, 2005 3:57 am

just keep in mind that if you're using phantom power to microphones, you want to be sure its switched off before plugging and unplugging...

That is correct. That's why my first suggestion was to hard wire directly into the mic inputs. But I myself prefer to have the mic tie lines come up on the bay so they can be rerouted as needed. Just as you said though, always keep that phantom power in mind. The best thing is to patch your bay before plugging in the mic.

That's why they call it "Pre-Production". Make your notes and wiring setup first.