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Splitting signals for monitors

Discussion in 'Sound, Music, and Intercom' started by kovacika, Dec 12, 2006.

  1. kovacika

    kovacika Active Member

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    I was wondering how I might be able to split signals to go to a monitor board, and front of house. I have worked with mixers that had this function built in (Midas, Yamaha) but this is for my personal sound system with boards not quite as full featured as the aforementioned. I need to split 10 xlr lines, the rest can go straight to FOH. If anyone has any suggestions I would be very pleased to hear any and all.
     
  2. sound_nerd

    sound_nerd Active Member

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    A proper split snake, or use the direct outs....otherwise I'm at a loss for ideas. But it's also late at night after a long load out day.
     
  3. kovacika

    kovacika Active Member

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    Thats what i thought, but im kinda hoping theres a short cut because i dont have a grand or two to drop on a splitter snake.
     
  4. Chris15

    Chris15 CBMod CB Mods Premium Member

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    From memory, the considered opinion is that for just a 1:2 split, you can normally get away with a simple passive split. For more than that you need transformers and / or active splits. Basically, it is a case of wire two male to a single female = Y split. One goes to FOH, the other to monitors. But beware that in this case, I seem to recall that the settings on one console can have an effect on the other. You also need to make sure that only one of the consoles supplies phantom to the lines. If you can't disable the phantom on one of them, a transformer may be neccessary. Or you could add a capacitor into the signal lines of one of the splits to block the DC. Probably it would be best to feed all phantom from FOH rather than monitors for the sake of consistency.

    Just some food for thought.
     
  5. kovacika

    kovacika Active Member

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    Does anyone know how the consoles will effect each other? That seems like a kind of scary thought. Also is it possible that the phantom power could damage the preamps on one of the consoles when just using a simple y adapter?
     
    Last edited: Dec 12, 2006
  6. Chris15

    Chris15 CBMod CB Mods Premium Member

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    Thinking more about it, I may have been mistaken. I have a nagging doubt that the settings affecting one another was to do with digital consoles using a single set of preamps to feeed both FOH & monitor and the gain adjustment on the preamp from one console will obviously affect the other.

    Not sure what effect the phantom would have. To be safe rather than sorry, put a capacitor in each of the audio lines (so both pin 2 & 3 of each channel) on the feed to the console not sending out the phantom. That will block the DC whilst allowing the audio to pass.
     
  7. kovacika

    kovacika Active Member

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    What capacitor specs would i be looking at?
     
  8. audioslavematt

    audioslavematt Active Member

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  9. SHARYNF

    SHARYNF Well-Known Member

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    All sorts of myths on this topic
    Here is my take on it.You can take you existing stage box, open it up, wire in another multi cable to each of the xlr, and add a ground lift for all the feeds to the monitor mixer. Some of the expensive transformer units have individual ground lifts, but

    IMO lifting all the ground for the monitor works for just about all cases.

    A transformer does NOT change the load the mic sees, but in todays world, for a two way split, not a problem.
    One console does NOT affect the other (other than it is a good idea to make sure that both are on the same power source.

    Some digital splitters do have a problem in that they place the split after the preamps, and so if you adjust the trim on the input preamp it affects all signals fed from it.

    If you have the budget wire in a mass connector, this way if you are not using the split you don't have the open cables that would have gone to the monitor connected to the mic inputs.

    Phantom power is not a problem, a system that can feed phantom power can accept phantom power. It is typically to feed phantom from the foh since you may not split all inputs to the monitor

    It works great, makes monitor mixing much easier, also this is how a lot of recording set ups are done

    I would say that if you need to have a three way split say for monitors and recording then iso transformers are best since splitting the mic signal three ways can be a problem.

    Using the direct outs can be done, but IMO is not worth the effort since you then have to feed the directs back via a snake to the monitor console on stage (for recording where the recorder is by the FOH it can and does work and is another way to have the split for monitors and the direct out for recording)

    Sharyn
     
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  10. Scooter

    Scooter Member

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    so, here's my take on all this for the cheapest version. you use a Female to two Male XLR adapter like the one shown below and plug the female end to the mic, a male end to the monitor board, and the other male end to the foh board? i think this would work, please correct me if i am wrong.
    [​IMG]
     
  11. mbenonis

    mbenonis Wireless Guy Administrator Premium Member

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    Here's a white paper written by Jim Brown, a well-known audio engineer who is considered an expert in many areas related to sound installations. It describes the many ways to split an audio signal, and what kind of split to use when.

    http://www.audiosystemsgroup.com/Mic_Splitters.pdf
     
  12. SHARYNF

    SHARYNF Well-Known Member

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    It works but it usually is not practical. The usual purpose of a monitor mixer is obviously for individual control of the monitor mix but almost as important is to move the function to the stage area and not co locate it at the FOH position.

    SO, typically the easiest way is as I said to wire in a connection on your stage box. An alternative is to make up a stage box that is a series of female xlr to dual male xlr's and use jumper cables to connect to your main snake, but this adds a lot of cost. IMO the simplest and easiest is to wire in a multi cable, run it to your monitor position and have just added xlr males to connect to your monitor mixer. As the white paper talks about, having a way to lift the shield (pin 1) on the monitor end is a good idea. ALSO IMO in the type of systems people on this board are likely to be involved in, running the FOH and Monitor from the same power source resolves a lot of the pin 1 issues

    Sharyn
     
  13. stjc15

    stjc15 Member

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    I have heard that splitting a signal can effect the impedence of the mic. Is this true?
     
  14. SHARYNF

    SHARYNF Well-Known Member

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    It does not change the impedance of the mic, but it changes the impedance load the mic sees. With a two way split it is not an issue

    Sharyn
     
  15. kovacika

    kovacika Active Member

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    I like the idea of adding a mult to my existing snake but wondering if anyone had tips on soldering in close quarters like that. Ive always been a bit of a hack with solder, it gets done but it doesnt look pretty and probably took longer than it needed to.
     
  16. SHARYNF

    SHARYNF Well-Known Member

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    Most of the multi's are pin based some are crimp and some are solder. Get your self a decent quality (weller for instance) with a fine tip, and practice. ;-)
    most people starting out, use too big an iron, heat the wrong thing, and don't use a small clip to hold the work

    Sharyn
     
  17. JSFox

    JSFox Active Member

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    If you don't use a proper splitter keep an AC ground lift handy for your monitor board (and make sure your FOH board is properly grounded).

    Note from Andy: This is neither safe, nor legal. There are right ways to fix a buzz problem. This is NOT, I repeat NOT it. 3-to-2 pin AC adapters are not AC ground lifts. They are ground adapters, intended to allow you to connect the ground pin of a 3-pin connector to the screw of a 2-pin outlet, provided that said screw is connected to metal conduit and thus, eventually, to ground.
     
    Last edited by a moderator: Dec 16, 2006
  18. SHARYNF

    SHARYNF Well-Known Member

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    This is NOT recommended, especially on a monitor board that is connected to the mics that the artist is going to be holding in their hands. this is how people can get hurt.

    Your ground lift should be on the INPUT side NOT the ac side, from an audio side of things lifting the ground on the input will have the same effect but not be dangerous. Lifting AC ground on sound equipment if very very dangerous especially when it is on the mic or instrument side of things. People have gotten really hurt based on a problem with say a guitar amp that had a bad ground system and fed ac voltage into the system, back to someone holding a mic in their hand etc.

    I do recommend running the monitor and the FOH on the same power connection/ground. Even though you would think different, in many pro festival setups, you wind up running a power cord back to the FOH system along side of the main audio snake, and do NOT have any problems, as long as all the feeds in the snake are balanced.

    Sharyn
     
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  19. silvrwolf

    silvrwolf Member

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    A cheap and highly un ethical way to split an audio signal for monitors or what ever is to use the channel insert jacks on your main boared as just an output. For example, on the main console if you take a TS plug (mono) and insert the plug partially into the first click of a channel insert jack, then you get a direct out to send to the monitor console. Then you take the other end of the cable and plug it into a line input on your soon to be monitor console. This is an ok idea it will allow you to get a direct channel out without phantom problems but it will probally lead you to a world of frustration due to ground loops and hum. It never hurts to try though. See the picture if you get confused about not fully plugging in the cord.[​IMG]
     
  20. mbenonis

    mbenonis Wireless Guy Administrator Premium Member

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    I second Sharyn's advice. NEVER use an AC ground lift, ever! It's just not safe.
     

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