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Routing Sound for a Musical

Discussion in 'Sound, Music, and Intercom' started by Stevens R. Miller, Mar 20, 2017.

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  1. Stevens R. Miller

    Stevens R. Miller Active Member

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    I have my community theater company's Behringer Xenyx 2442FX mixer on loan from them in my home. This is a real treat because I've never had extended time with a mixer before. Finally, I'm getting a chance to learn something more about them than just their simplest many-in-two-out "funnel" mode.

    The Xenyx has eight mono input strips and four stereo input strips. It has four auxiliary sender busses and can assign any input to the Main bus, the Subgroup 1-2 busses, the Subgroup 3-4 busses, or to any combination of busses. The Subgroups can themselves be assigned (right word?) to the left or right channel of the Main bus, or to both.

    When we do a musical, we use a pre-recorded soundtrack and wireless mikes for the actors. We typically have access to two amplifiers, using one to drive the house speaker, and one to drive the stage monitors. For the house, we want both the soundtrack and the mikes to be amplified. For the monitors, we only want the soundtrack. Our sound tech has achieved this in the past by using the pan control on each input, setting it to center for the soundtrack, and fully to the right for the microphones. That way, both the music and the voices are on the right channel, but only the music is on the left channel. We feed the left channel to the monitor amp, and the right channel to the house amp.

    This scheme works, but it leaves us reliant on Behringer's electronics expertise to fully separate the mikes out of the mix, and also deprives us of the ability to set the monitor levels indepedently of the house speaker level.

    After some experimentation, it seems to me that a potentially superior configuration would be to assign the microphones all to Subgroups 1-2, and assign the soundtrack to Subgroups 1-2 and 3-4, then assign Subgroups 1-2 to the right channel of the Main mix, and Subgroups 3-4 to the left channel of the Main mix. This again has both mikes and soundtrack on the right channel, for the house, but only soundtrack on the left channel, for the monitors. With this setup, I can set the house and monitor levels independently, by adjusting the Subgroup masters (1-2 for the house, 3-4 for the monitors).

    Now, I could just use the Subgroup outputs off the back of the mixer directly, and skip the part where I assign them to either side of the Main mix. But, that would mean my stereo sound track would be delivered in stereo to the amplifiers, which I don't want. For amplifiers that have a "mono" button, that's not a problem. But, not all of them do have that button and, for some, it appears that feature is buried in a complicated user-interface I won't always understand. To get around this issue in the past, we've fed our stereo soundtrack into two input strips and just made each channel part of the mix. That, however, wastes an input we'd rather have open for another mike. So, I'd prefer to feed stereo into a stereo input, and "mix" the channels by assigning both Subgroups in a given pair to the same Main bus output channel. (That is, when I feed stereo into a stereo input, and assign that input to Subgroups 1-2, the left channel of my input appears on Subgroup 1, and the right channel is on Subgroup 2. To mix them down to mono, I assign both Subgroup 1 and Subgroup 2 to the right channel of the Main mix, which then goes on to feed the house speaker in mono.)

    Given that there are four auxiliary senders, two of which can be set to operate pre-fader, I can see there are other ways to do what I'm trying to accomplish. The monitor amp could be fed from one of the auxiliaries, for example.

    So, I'm looking for advice on good configurations for using this kind of mixer to accept a stereo soundtrack in, along with several wireless mikes, in order to drive two amplifiers, each in mono, one with soundtrack-plus-mikes, one with just soundtrack.

    All suggestions are gratefully received.
     
  2. microstar

    microstar Well-Known Member

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    Here's what I would do:
    Send the music via a stereo line input to Aux 1 and set Aux 1 to Prefader. Run Aux 1 output to your onstage monitor speaker amplifier.
    The block diagram is your friend. Follow the lines from the stereo inputs on the left of the diagram and you will see they are by default combined to mono as they continue on to the Aux outputs. Prefader means the channel fader does not affect the level sent to Aux's.
    Also send music stereo line input to Sub 1 and 2. Send groups of mics to Subs 3 (chorus) and 4 (principals). Send all 4 subs to Left Main only.
    Therefore the music will be in mono to the main speaker amplifier as well and you have group control of chorus and principals mics.
    Left Main out runs to main amplifier. I'm sure there are many other ways to do this.... just the first thought that comes to mind. One issue with this approach is that AUX sends on this mixer are unbalanced, which may or may not be a problem.
    BlockDiagram.jpg
     
    Last edited: Mar 20, 2017
  3. Stevens R. Miller

    Stevens R. Miller Active Member

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    Hey, where'd you find that? My manual doesn't have one.

    Good point about the Aux senders mixing the stereo inputs down to mono. Solves my problem much more simply.
     
  4. microstar

    microstar Well-Known Member

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  5. Stevens R. Miller

    Stevens R. Miller Active Member

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  6. jkowtko

    jkowtko Active Member

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    Do you have stereo main PA in the theater? If so, why wouldn't you want to play the music tracks in stereo? Unless you have a lot of hard panning in the music tracks, stereo sound comes out much more "relaxed" when played in stereo vs mono. Mono can sometimes give you a headache. That's just my opinion though ...

    -- John
     
  7. Stevens R. Miller

    Stevens R. Miller Active Member

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    Our auditoriums ("auditoria?") generally have a single loudspeaker, hung high over the stage. With two speakers in stereo, I'd expect a lot of people would be hearing one channel over the other.
     
  8. TNasty

    TNasty Member

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    Boy do I love using aux's and groups for stuff like this. In the production of Jesus Christ Superstar I was running sound for last week, I literally abused the use of groups- Groups 1/2 were the choir mics, Groups 3/4 were the pit (Strings/Wind respectively, they only went to the groups, which then went to center), 5/6 were Mary Magdalene's maids (they went directly to center, and to the groups, which were used to easily boost them when they had their moments), and 8 was used for the talk-back microphone.

    My advice is that if you route everything through your main out, then you can use your aux or group sends for the monitors. If I'm not mistaken, Aux's are typically pre-fade sends.
     

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