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I am getting into producing DVDs of live music performances.
In order to provide the best possible sound quality for my finished video, I must make a multitrack recording of the performance.

As we all know, a L/R feed of the FOH mix is almost never satisfactory for a recording. I need a way to get the best audio for my video possible, without setting up all my own mics. This means I must use audio from the mics that the FOH guy sets up. I think the best answer is to use a splitter snake. Due to budget constraints, I want to build my own transformer-isolated splitter snake. The direct side would go to the FOH board, and the isolated side would go to my board. OBviously I need a 1:1 transormer.

My question: What specs should I look for in my transformers? Any specific brand and model you can recommend?

Thanks! - Jerry

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Kapt.Krunch Sat, 03/24/2007 - 06:16

Here's the first name that popped into my head. There may be other, better ones:

There may be an alternative method that doesn't require buying a lot of transformers, a metal box, a large spool of cable, a whole bunch of XLRs, and a tremendous amount of time. May not be as budget-friendly as you would like. I guess there's always the possibility of trying to use an existing snake, and modifying it, if there is room enough inside? I dunno.

If your recording mixer that you will use is capable of passing a balanced direct signal, pre-fader and pre-EQ, and it has as at least as many channels as the FOH requires, you may consider running everything first to your mixer, then direct out to the snake to the FOH. All you may need to buy or construct are some TRS-to-XLR cables, if your direct outs are TRS.

Why to yours first? Because the FOH may be using its direct outs for other things. It kind of depends on where you set yourself up, also, I guess. if you are next the FOH, and they are have all their direct outs available, you could do it the other way around, with their direct outs feeding your mixer. Of course, it may be that their direct outs are running back to the stage for monitor mixing. Depends how they do it.

But, if you are stageside, it would be rather silly to take their direct outs, if available, and run another long snake back to the stage for you. May be easier to just run everything the relatively short distance to you, then on through a snake to the front. Then the FOH could provide the monitor mix...if that's how they are doing it. Also, one may assume that you want to run through minimal effects or other fancy stuff that would use your direct outs, leaving yours free, but the FOH may.

That's one of the things pre-fader and pre-EQ direct outs are for. The mixer manufacturer pretty much just built in a splitter. Tap it at the input, send this to the direct out jack, and that through the circuitry. No matter how much the other guy mangles HIS mix, he can't mess up yours...unless he causes the stage mics to pick up feedback and other stuff.

Then there's always the possibility that you can buy a snake that is already configured the way you want, if you need to use it. I have no idea if they exist, or who makes them. May even be less expensive than building one, after all the parts costs are added up. And your time. If you build a 24 channel single snake (not split), that's two ends=48. 48x3 pins each is 144 solder joints. Now add to that whatever you will need to do to add the transformers to each cable to split. Got a free weekend to do nothing but solder? And how long does each cable of the split need to be? Do you do a few hundred feet for FOH, and less for the recording side? Is this going to be pretty much the same scenario each time you do this?

Of course, there may be other considerations and problems using a scenario that runs everything first to your mixer, then direct out to the front, and then possibly their direct outs back to a monitor mixer. That's a long route each signal must take. It may all depend on the mixers' capabilities and designs themselves. Then of course, there are electrical considerations, if the mixers are running from different circuits. May be that you absolutely DO need isolation transformers of some sort, and have no choice. May be that your idea IS the best one.

Anyway, I'm just throwing stuff at the wall, as usual, to generate ideas, more opinions, and healthy debate. I may have it ALL wrong. This is just stuff that popped into my early-morning, four Guinness last night slightly addled brain that may be worth considering. (I know I'm getting old when only 4 Guinness makes me a bit cruddy in the morn!) :shock:

The floor is open....

Good luck,


Scoobie Sat, 03/24/2007 - 08:14

I usally do the FOH mixing also when recording live shows. Thats the best way IMO. Then you don't have to worry about the signal going into your converters peaking as much.

If your not doing the FOH mix, some boards have direct outs and inserts. Check with the live sound guy and you should be able to use one of them.
But you still have to worry about the FOH srewing with the mic pre gain because that will effect the signal going into your converters. That can be a recipe for disaster if they don't have a good sound engineer.

Sometimes its best to record the 2nd set. That way the 1st set can be a trial run.....YMMV

Hope it truns out well for ya,


anonymous Sun, 03/25/2007 - 21:10

Thanks for all the feedback guys. The shows I intend to record this summer are low budget affairs in low budget venues, with low budget PA systems.

I will be FOH engineer if possible, but I'm nonetheless dead set on a solution that doesnt involve "contaminating" the signal with whatever kind of crappy pres that the FOH board has in it. My setup will most likely not involve a board, instead going direct into a Firepod interface using its internal pres. I will probably have to make some exceptions for channels that will need processing before they go down to "tape". Any suggestions as to these types of techniques would be greatly appreciated. There are several different schools of thought in this area, some prefer to capture everything and throw-away/process the signal later, while some people find merit in mild processing before capture.

Time and labor, such as soldering, is not a factor. Budget is THE factor.

I've recently read that its "ok" to split a balanced mic signal to 2 different pres without xformer isolation. What would be the feasibility of a splitter snake that isnt xformer isolated? The obvious advantage would be a substantial reduction in parts costs.


tnjazz Wed, 03/28/2007 - 11:48

We use passive non iso splits frequently in the clubs we work in. Many times the club provides the split, or it's hard wired into their system.

We have never had any issues caused by the snakes when using the passive non iso ones. We just took much greater care in checking lines and troubleshooting anomalies ahead of time.

If you're determined to make your own splitter, I'd start with a passive non-iso and then add transformers (or a separate transformer box even) as you can afford them.



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