Full-normalling VS. half-normalling the mic lines in a patch bay.

[ThatWasAwkward]

What would be the advantages of having the Ins and Outs of your mic lines full-normalled in the patch bay instead of half-normalled? Is there any reason you wouldn't want to have that specific thing half-normalled?

[cominginsecond]

You're running your mics through a patch bay?

[SonicAlbert]

I would want any mic preamps to be de-normalled to prevent any accidental pass-through of unwanted signal. I'd want to *have* to manually patch them from the front.

The way I have my preamps routed is that I have the outputs in the patchbay, but the inputs are not. The inputs are a couple of XLR cables I hve loose, placed where it is easy to get at them. I just don't like the idea of patching mics through a patchbay.

[Track Rat]

Bad Mojo to have mics in the patchbay. That could be a REAL big problem with phantom power. I have all the mic inputs hard wired from a plate in the wall in the sound room directlyto their respective mic preamp. The line outs from the mic preamps are in the patchbay for patching.

[Raw-Tracks]

I always hear people saying not to put the mic lines in your patchbay. However, I would say that in at least 90% of the professional facilities I have been in, the mic lines are in the patchbay. I've never had any problems with it. Granted these were TT and Longframe patchbays, not your average TRS bay. Don't know if that will make a difference, I doubt it.

Anyway, generally mic lines are full normalled to the mic pre inputs. Meaning, with no patch cable inserted, the signal will travel from the mic line on the top row, to the preamp in on the bottom row. If you want Mic line 1 to go to preamp 2, you run a patch cable. When you run the patch cable, the signal from Mic Line 1 will no longer travel to mic preamp 1.

[cominginsecond]

Every pro facility I've ever seen has mic connectors in the wall that go to the preamps. I really want to do that one of these days, rather than having to constantly reach behind my rack in feats of acrobatic skill.

[bounce]

For mic inputs in a patchbay, I would recommend using an XLR bay to patch them into pre's. The reason for this is that the 3 pins of an xlr are kept separate when connecting. If you accidentally have phantom power enabled on a pre and you are using TRS on the bay, the tip of the connector will pass through the other pins (ring, sleeve) to get to the tip connector in the bay. This means for a second, phantom power will be going down the wrong pin and can damage the subsequent gear.

Cheers,

Mckay Garner
Bounce Inventive Audio
Los Angeles

[Raw-Tracks]

Originally Posted by cominginsecond

Every pro facility I've ever seen has mic connectors in the wall that go to the preamps.

Without going through a patchbay? Take a look at a stock SSL, Neve, or Trident console's patchbay. They all have a row of mic lines and mic preamp lines.

[Raw-Tracks]

Originally Posted by cominginsecond

I think we have some confusion here. You're saying that pro studios plug their mics directly into TT or TRS patchbays? I've never heard of such a thing. Every picture I've ever seen of a studio has XLR snakes that go out from the pres and into the tracking rooms. Then the line outputs of the pres are routed through a patchbay.

NO.

I generally see a couple of XLR panels out in the studio and the various iso booths. Those panels are wired to a row in the patchbay. That row in the patchbay, often the very first row, is then fully normalled to the next row in the patchbay. This 2nd row in the patchbay is where the console's mic pre's are accessed.

In other words, when you plug into the MIC-1 input, out in the studio's XLR panel, the signal is routed directly to Channel 1 on the console. The mic signal goes through the patchbay though. That way, for example, when I plug the Room Mics into mic lines 33-34 in the back of the room, I can bring them up on Console Channels 11-12 by cross-patching the mic lines.

[cominginsecond]

I started this thread over at gearslutz for more conversations about phantom through a patch bay:

http://gearslutz.com/board/showthrea...03636&posted=1

I'm learning something every day. I thought that mics and patch bays never mixed. It appears that answer is more complicated than that.

[cominginsecond]

Originally Posted by Raw-Tracks

NO.

I generally see a couple of XLR panels out in the studio and the various iso booths. Those panels are wired to a row in the patchbay. That row in the patchbay, often the very first row, is then fully normalled to the next row in the patchbay. This 2nd row in the patchbay is where the console's mic pre's are accessed.

In other words, when you plug into the MIC-1 input, out in the studio's XLR panel, the signal is routed directly to Channel 1 on the console. The mic signal goes through the patchbay though. That way, for example, when I plug the Room Mics into mic lines 33-34 in the back of the room, I can bring them up on Console Channels 11-12 by cross-patching the mic lines.

I see what you're saying, but lots of folks that are responding, both on this thread and on the gearslutz thread, are saying they don't feel comfortable running phantom through any but an XLR patchbay. I guess I was just under the impression that this was a no-no, but apparantly it depends on the person/studio.

[thediscoking]

The mic signal goes through the patchbay AFTER the preamps at line level and free of phantom power.

Mic -> Pre -> Patchbay -> etc.

[Raw-Tracks]

Originally Posted by cominginsecond

but lots of folks that are responding, both on this thread and on the gearslutz thread, are saying they don't feel comfortable running phantom through any but an XLR patchbay.

If your definition of "lots" is 1 or 2, then yeah. I count one guy on that thread, as of right now, that says don't run mics into the patchbay.

[Raw-Tracks]

Originally Posted by thediscoking

The mic signal goes through the patchbay AFTER the preamps at line level and free of phantom power.

Mic -> Pre -> Patchbay -> etc.

NOT ALWAYS!

Have you people ever seen an SSL patchbay? That's just one example of a stock patchbay that comes from the factory with mic patching onboard. Why would they facilitate mic patching in their patchbays if it was harmfull to other components in the signal path?

I think this whole myth of not running mics through the patchbay comes from the fact that you usually get a loud, nasty pop that can blow your speakers if you don't mute the channel first. That's what the MUTE button is for.

[cominginsecond]

Originally Posted by Raw-Tracks

If your definition of "lots" is 1 or 2, then yeah. I count one guy on that thread, as of right now, that says don't run mics into the patchbay.

4 on this thread, 1 on the GS thread are not comfortable with running phantom through the patchbay.

Your approach is fine, but you shouldn't pretend that there's no disagreement here, and that it's a completely settled issue.

[thediscoking]

Originally Posted by Raw-Tracks

NOT ALWAYS!

Have you people ever seen an SSL patchbay? That's just one example of a stock patchbay that comes from the factory with mic patching onboard. Why would they facilitate mic patching in their patchbays if it was harmfull to other components in the signal path?

For home recording purposes, the patch bay should, usually, come after the pres.... that's what I was talking about.

Yes, I have worked on an SSL.

I'm not an electronics wizard, but I don't see how phantom power could run through a TT (like the SSL has), since XRL uses hot, cold and ground pins. I don't think it's possible.

If anyone knows otherwise, do share


Another thought.... if one were to use the mic inputs on an SSL patchbay, where would the signal come from??? XLR to TT???????? I never thought about that.

[Raw-Tracks]

Originally Posted by thediscoking

For home recording purposes, the patch bay should, usually, come after the pres.... that's what I was talking about.

That is, if you like crawling behind your rack to patch mics into your preamps.

I'm not an electronics wizard, but I don't see how phantom power could run through a TT (like the SSL has), since XRL uses hot, cold and ground pins. I don't think it's possible.

If anyone knows otherwise, do share

A TT cable is like any other balanced connection. An XLR has three pins, and a TT has a Tip, Ring and Sleeve. A TRS can carry phantom as easily as an XLR.

[thediscoking]

Oooohh. Okay.

[thediscoking]

Originally Posted by Raw-Tracks

That is, if you like crawling behind your rack to patch mics into your preamps.

If the mic inputs on your patchbay are normalled to your multi-track inputs, no crawling required.

Unless, we're talking about two different things.

[Raw-Tracks]

Originally Posted by thediscoking

If the mic inputs on your patchbay are normalled to your multi-track inputs, no crawling required.

Unless, we're talking about two different things.

I'm talking about mic lines from the studio's mic panel, coming into the studio and being wired into the patchbay. From there, they can be patched into any mic preamp you desire. That is before the mic signal hits a preamp. Well before you get to any multi-track recorder input.

[xstatic]

Most big studios do have their mic lines on a patchbay. Especially when you are dealing with multiple rooms, lines etc... They don't want you crawling around the back of the racks all the time. However, most of the big studios also have QUALITY paychbays and not some cheap $100 or less bay. They also use solder and punchdown patchbays to maintain a good connection. If a system is properly grounded, and proper precautions are takes a patchbay is just fine to have in line. It isn't any different than a wall panel or a snake box when it is done properly. XLR patches are an excellent way to do things because the connection is solid, but XLR plugs can still arc if there is a problem somewhere. In the end it boils down to how well the system was implemented and installed and not which style of plug you are using or whether or not you are using patchbays. The shortest path is still the best path, but is certainly not always the fastest path. If someone had to climb behind my console and racks every time they wanted to change a patch, then my cables would constantly get destroyed, plugs get unseated etc... That is never good for a session.

[ThatWasAwkward]

I guess I should perhaps be a little more specific about the patchbay I'm referring to. The top row is the outputs from the mics, and the bottom row is the channel mic inputs going into the preamps of an SSL G-Series console. The patchbay itself uses TT cables.

So, back to the original question: Would there be any compelling reason to avoid having those two rows half-normalled?

[Raw-Tracks]

Originally Posted by ThatWasAwkward

So, back to the original question: Would there be any compelling reason to avoid having those two rows half-normalled?

You don't want those 2 two rows to be half normalled. They should be full normalled. The reason is, when you patch Mic Line 1 over to Mic Pre 2, if it is half-normalled your Mic Line 1 will be gonig to Mic Pre 1 & 2. In a fully normalled configuration, when you patch into the top row, it breaks the normal to the bottom row. In a half normal, the signal is split when you patch into the top row. You don't want your mic signal to be split into 2 mic pre's.

Mic lines from the studio should always be Fully Normalled to the Mic Pre's.

[TornadoTed]

I've got the 2 main live areas, 2 booths and mic pres coming into XLR patch bays. Totally isolated no normalization at all, I've never had any problems.

[ThatWasAwkward]

Originally Posted by Raw-Tracks

You don't want those 2 two rows to be half normalled. They should be full normalled. The reason is, when you patch Mic Line 1 over to Mic Pre 2, if it is half-normalled your Mic Line 1 will be gonig to Mic Pre 1 & 2. In a fully normalled configuration, when you patch into the top row, it breaks the normal to the bottom row. In a half normal, the signal is split when you patch into the top row. You don't want your mic signal to be split into 2 mic pre's.

Mic lines from the studio should always be Fully Normalled to the Mic Pre's.

Yeah, you are correct. I finally figured it out. You shouldn't have one mic connected to two preamps because you could end up accidentally sending 96v of phantom power into a condenser mic, which would likely permanently damage it.