Splitter for Mobile Rig

[nixoblivion]

I'd like to build a mobile Rig for 16 Channels. It should stay very basic, so i would just use audio interfaces and go straight in to my laptop.
This will mostly be used for live recording

Now the question is about splitting the signal comming from the Stagebox. Splitboxes are definatly not cheap and you still need to get 32 xlr cables, which can be quite expensive as well..
So i was wondering if the same thing would work with simple Y-cables. Can these be problematic? what happens with the ground?

[rcrowley]

Originally Posted by nixoblivion

So i was wondering if the same thing would work with simple Y-cables. Can these be problematic? what happens with the ground?

Simple Y-cables CAN work in SOME cases, but it is ALWAYS risky and NEVER optimal. For portable use in varying situations, using Y-cables is NOT recommended. The technique is overloaded with potential problems under the best circumstances. What happens to the ground is only ONE of the potential problems.

If you want something reliable, but low-budget, you could investigate using something like these:

EWI MST-412 4 Channel 3 Way Rackmount Passive Transformer XLR Splitter $105
MST-412

[philper]

Originally Posted by rcrowley

Simple Y-cables CAN work in SOME cases, but it is ALWAYS risky and NEVER optimal. For portable use in varying situations, using Y-cables is NOT recommended. The technique is overloaded with potential problems under the best circumstances. What happens to the ground is only ONE of the potential problems.

If you want something reliable, but low-budget, you could investigate using something like these:

EWI MST-412 4 Channel 3 Way Rackmount Passive Transformer XLR Splitter $105
MST-412

I did lots of live recording for years w/ simple Y cables and passive hard splitter boxes w/o issues. Now I use a rack of splitters mostly. Why? because there is still the POTENTIAL for a problem, I like having the ground lifts etc available to solve issues if they arise, and I get less argument from house sound people about the split (most important aspect).

phil p

[Murton]

Whirlwind SB16T11G - $940.
4x 8 channel XLR looms - $40 each, $160

or

2x ART S8 Splitter $199 each, $400
2x 8 channel XLR looms - $40 each, $160

There you have it, decent option with a Whirlwind splitter for great quality for both splits and ground lifts and transformer isolated output which should solve most problems when it comes to splitting. And the cheap option with the ART S8's which still sound alright but have a pretty high THD but for the money will get the job done.

[nixoblivion]

Thanks for your replies!

So what do you guys mean when you say CAN cause problems. what sort of problems? When do these occur?
Im the house engineer in a small venue and i would use this recording solution for that location mostly, but with option of taking it otherwhere too.

The problem is the 16 channels of recording will cost me 800€ already. The cheapest splitters i found were 160€ for 8 ch. so another 320€ just for splitting and then ill need another 4x 8 Multicore kabels (2x8 going to the mixing desk, 2x8 going to the preamps) costing 120€ still.
Is there no cheaper way in splitting 16 channels??

Originally Posted by philper

and I get less argument from house sound people about the split (most important aspect).

phil p

haha, nice one!

Originally Posted by Murton

Whirlwind SB16T11G - $940.
4x 8 channel XLR looms - $40 each, $160

or

2x ART S8 Splitter $199 each, $400
2x 8 channel XLR looms - $40 each, $160

Well first of all, the ART S8 costs 320€ here in europe! I hate the prices here...
But i found an equivalent at thomann for 160€.

[rcrowley]

Here are a few potential problems to get you started. This is not an exhaustive list. I'm sure others here can add to this list...

1. Cooperation from venue/FOH System Even if you have a world-class, well isolated (with premium iso transformers, etc) system, there are dozens of reasons for the people running the "main" system to simply deny you access to interrupting their mic lines. If you were in their shoes, you might very well do exactly the same thing. It is a big risk on their part to let some 3rd party come in and interrupt their signal, especially when THEY are on the hook for delivering a good show, and you have no liability for screwing them up. I suspect that you may not appreciate how big a deal this is.
   
2. Shielding/Grounding/RFI Issues Interconnecting different systems, especially at a point where you have such a vulnerable signal (mic level) is always tricky. That is why the good solutions use transformer isolation AND Ground Lift switches. You never know whether joining or separating the grounds will be the better solution because there are so many unknowns, especially in portable, transient systems.
   
3. Impedance Loading Issues There is no perfect splitting system. Any of them will result in some compromise to the impedance loading of the microphone. Perhaps in a head-banging heavy-metal noise-fest this is not an issue. But there are SOME occasions where this is a significant factor.
   
4. Phantom Power Issues Which user supplies condenser mics, direct boxes, etc. with phantom power? What happens if other parties switch their phantom power on or off during the show? How do you prevent one person's phantom power from being fed into somebody else's input, especially those that don't tolerate phantom power?

I have been personally bit by most of these issues and I don't do a fraction of this kind of gig as many people here do. And you can multiply each of those by 10 (or maybe 100) if you are talking about using hard-wired Y-cables. IMHO, that is such a bad idea that I don't even seriously consider it a viable alternative.

If YOU are the owner of the "main" system and YOU are wanting to track the channels, why would you fool around with mic-level splits? The channel outputs (or insert points) on the mixer/desk are a much safer place to tap the signal with significantly less risk to the prime directive (FOH/monitor mixing).

[nixoblivion]

rcrowley, thanks a lot for your detail!!!!

Originally Posted by rcrowley

Cooperation from venue/FOH System Even if you have a world-class, well isolated (with premium iso transformers, etc) system, there are dozens of reasons for the people running the "main" system to simply deny you access to interrupting their mic lines. If you were in their shoes, you might very well do exactly the same thing. It is a big risk on their part to let some 3rd party come in and interrupt their signal, especially when THEY are on the hook for delivering a good show, and you have no liability for screwing them up. I suspect that you may not appreciate how big a deal this is.

Well i am House sound engineer in a place and ive always let the people split to get their signals into their interfaces. I've hab both, split boxes and y splitters and never had problems. Thats why i dont know where the problems can occur!

Originally Posted by rcrowley

Shielding/Grounding/RFI Issues Interconnecting different systems, especially at a point where you have such a vulnerable signal (mic level) is always tricky. That is why the good solutions use transformer isolation AND Ground Lift switches. You never know whether joining or separating the grounds will be the better solution because there are so many unknowns, especially in portable, transient systems.

So you mean that the splitter must have a galvanic seperation? And that also means i will have to check every single channel for hums (ground lift). But could it happen that one split (going to the desk) needs to be lifted and the other (going to the interface) not?

Originally Posted by rcrowley

Impedance Loading Issues There is no perfect splitting system. Any of them will result in some compromise to the impedance loading of the microphone. Perhaps in a head-banging heavy-metal noise-fest this is not an issue. But there are SOME occasions where this is a significant factor.

But this will be no problem with a dedicated splitter?

Originally Posted by rcrowley

Phantom Power Issues Which user supplies condenser mics, direct boxes, etc. with phantom power? What happens if other parties switch their phantom power on or off during the show? How do you prevent one person's phantom power from being fed into somebody else's input, especially those that don't tolerate phantom power?

Well i will be the one running the FOH desk AND the interfaces! So i would choose to send the 48v from the desk and leave it at that! Then everything should be fine right?

Originally Posted by rcrowley

If YOU are the owner of the "main" system and YOU are wanting to track the channels, why would you fool around with mic-level splits? The channel outputs (or insert points) on the mixer/desk are a much safer place to tap the signal with significantly less risk to the prime directive (FOH/monitor mixing).

Unfortunatly the mixer where i work has no direct outs, otherwise we wouldnt have this discussion! The problem with using the inserts is 1. they have balanced cable inputs (inserting an unbalanced cable would work, but with bad luck i would cap the signal!!) 2. I cant use compression in my inserts anymore! 2. isnt the biggest problem, but 1. does worry me a little. I think i would encounter less problems if the signal is split before hand!!

[rcrowley]

While your subject line says "Splitter for Mobile Rig", you are discussing a fixed system where you have control over all the variables. That is a MUCH different situation than what likely most of us would think of in terms of a "mobile rig" where we not only have no control over the house/main system, but frequently no information about it either. And then add to that the knowledge, cooperation, and even mood of the resident operator and the situation is very different than what you are describing.

Your POV from being the operator of a fixed system is very different than from the other side of the cable when you are called in to record in a new, unfamiliar venue.

[philper]

I think you might not fully appreciate the politics involved in being an outside recordist trying to do a full split recording of a live show. It's easy (and tempting) for a FOH mixer who might be overworked, underpaid, harassed and under pressure to make things hard (or impossible) for that outsider. The perception of the lay of the responsibility for the live show has already been described above, and there is no question that adding a recording split always adds several new possible points of trouble for the live show. Unless I've worked with them before the FOH people have no idea if I know how to solder a Y cable etc, but they do know that Whirlwind or Rapco etc DO know how to make a splitter. I understand how they feel. In many situations there may be an insistence on my taking direct out feeds (if they are available) because of them not wanting to interrupt their mic level lines--if that's all I can get then I'll roll with it. In making the case for a mic level split (my pref always) having the splitters and new-looking cables and snakes can help close the sale.

phil p

[nixoblivion]

Ok yes, you are right. If i were otherwhere i would probably not dare to use y adapters, true. Though i must admit i have let other engineers use them at our place, as long as it works during soundcheck, why not.

But yes in my case, my rig would not be as mobile. Still the point is, it should be mobile in case i need it elsewhere. Im guessing it will be used at the same place 80% of the time, maybe even more at first. But once things get rolling i will use it elsewhere...

So in this case what are your recommendations??

[rcrowley]

i have let other engineers use them [Y-adapters] at our place, as long as it works during soundcheck, why not.

You seem far more idealistic than most system operators. It is only a matter of time before you realize the pitfalls of that policy.

what are your recommendations??

It is not an accident that the traditional methods have become trusted and acknowledged as reliable:
1) Mic-level splitter transformers.
2) Line-level iso outputs from the mixing desk (or more dangerous, using the effects insert points)
3) Mic preamps with multiple outputs, one to house system, one for recording, etc.

I personally would never expect to walk into anywhere (even somewhere I had worked regularly and know the system and the operator) and use a hard-wired Y-adapter for mic level. And where I am the FOH operator, I wouldn't allow anyone else to do that to my system, either. You have simply been lucky that you haven't experienced one of the many potential problems with the scheme.

[nixoblivion]

Thanks.

I guess i only have one option!
Im just bumbed that the wiring + splitters + rack will be almost as expensive as the 16 channels preamp + a/d!!

But it seems i have never had problems with y adapters. i dont even know how those problems will unfold. Therefore i was never worried about it. And most of the time when that happens it is also the same engineer who is responsible for the concert, im just assistance and therefore it is pretty much his choice what he does!

[StewartFang]

How about you just rent a proper splitter on a per show basis and consider it a hard cost

[philper]

Another way of getting house people on my side is to offer to rent the splitter FROM THEM. They get a bump and the confidence in their own gear....

phil p