How do I Sum (or Pan) ST3 for a Mono Rig?

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This topic contains 13 replies, has 6 voices, and was last updated by Profile photo of Gordon Gordon 1 year, 6 months ago.

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  • #90270
    Profile photo of Gordon
    Gordon
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    I have a tablet that I use to play mp3’s during breaks at live shows. I plug it into the ST3 mini plug and it works pretty well except for one thing. If I setup my PA system to run in mono configuration, (using LEFT MAIN OUT only,) I cannot figure out how to sum both ST3 channels to the left output. When I select the ST3 channel and use the PAN knob to pan everything hard left, it only removes the music from the RIGHT MAIN OUT jack. It does not route the right side music information over to the LEFT MAIN OUT jack. In other words, it does not sum left and right. It only mutes the right side information.

    As an example, one of my songs is, “I Saw Her Standing There” by the Beatles. In my copy, (a remastered 2009 version,) vocals are in the right channel and instruments are in the left channel. I cannot get both vocals and instruments to pan to the LEFT MAIN OUT jack and we can’t hear any vocals.

    Any ideas what I am doing wrong?

    #90272
    Profile photo of volounteer
    volounteer
    Participant

    @gordon

    The hardware does not work that way with the stereo ST3 configuration you are trying to use.

    When we have split channels we run them into two adjacent input strips.
    You can pan those all L or R to ‘sum’ them to mono.

    Get a mini trs stereo to dual TS phono plugs and use two channels for summing.

    #90273
    Profile photo of Mike C
    Mike C
    Participant

    To save using two channels on your mixer you could use the ALT output to drive the system and in the IO set up menu for the ALT output select L+R (mono sum). The ALT output is 1/4 inch TRS balanced and not XLR.

    Another way that would be a little bit of a DIY project would be to make up a mono summing cable.
    Follow this link and look at figure 2 for the schematic that you would need. The only change would be the mono output side would connect to both the tip and ring on a 1/8 since you are using the ST3 input.
    MONO SUMMING

    I have made a couple of the balanced line versions and they work fine.

    #90278
    Profile photo of Gordon
    Gordon
    Participant

    To save using two channels on your mixer you could use the ALT output to drive the system and in the IO set up menu for the ALT output select L+R (mono sum). The ALT output is 1/4 inch TRS balanced and not XLR.

    It would be nice if I could just patch L/R main to mono sum in the same way. Perhaps in a future firmware update.

    Thanks, guys. This all gives me some ideas. I just wanted to make sure that I wasn’t missing anything hidden within the mixer settings.

    #90279
    Profile photo of Mike C
    Mike C
    Participant

    Lets think outside the mixer, what is the rest of your PA system, maybe there is mono
    sum option there some where.

    In the link I provided earlier you could build up the balanced line mono summing summing circuit and directly mono sum the main L R outputs.

    Whirlwind has this transformer isolated line level mono summing box, I have one of them
    I’ll use sometimes.
    Whirlwind mono summing box

    #90280
    Profile photo of Gordon
    Gordon
    Participant

    That summing box would indeed be useful.

    But wait! I do have an Ashly Protea signal processor. It can easily patch any input to one or more outputs and visa-versa. Done!

    #90281
    Profile photo of Mike C
    Mike C
    Participant

    But wait! I do have an Ashly Protea signal processor. It can easily patch any input to any of the outputs.

    There you go!
    Do the mono summing within the Protea set up, you can do an input mix function and then route that to your needed output processing functions.
    I haven’t programmed a Protea in a few years but I still have the software on my laptop!

    #90286
    Profile photo of garyh
    garyh
    Participant

    The nice thing about the A&H Stage Boxes, is the ability to assign L+R to one of its outputs. That’s what we do for my church’s mono PA system. It would still be nice if there was a L+R Sum option directly in the st1-3 processing panel.

    #90287
    Profile photo of Mike C
    Mike C
    Participant

    The nice thing about the A&H Stage Boxes, is the ability to assign L+R to one of its outputs. That’s what we do for my church’s mono PA system. It would still be nice if there was a L+R Sum option directly in the st1-3 processing panel.

    Good point on the stage box, I’ve done that for some fill feeds ect.
    Too bad the Protea does not take AES input, you can assign a summed mono output to the AES.

    #90377
    Profile photo of Painkiller Pete
    Painkiller Pete
    Participant

    What you need to do is just get a cable that is stereo on the mini plug end for the tablet into mono on the other end. That way both sided of the stereo signal are played back when you pan to the left or right.

    #90378
    Profile photo of Mike C
    Mike C
    Participant

    What you need to do is just get a cable that is stereo on the mini plug end for the tablet into mono on the other end. That way both sided of the stereo signal are played back when you pan to the left or right.

    That would work, but it is better not to do a hardwired direct connection between the left and right outputs of a device.
    The mono summing circuit I linked to earlier gives you some resistive isolation between the output channels.

    #90414
    Profile photo of debzdoodle
    debzdoodle
    Participant

    Do you have the ability to sum mono in the tablet? This can be done on iPads/iPhones etc.

    #90416
    Profile photo of Mike C
    Mike C
    Participant

    Do you have the ability to sum mono in the tablet? This can be done on iPads/iPhones etc.

    And we have a winner for the easy solution!!

    Didn’t know that setting existed, on my Android tablet the setting is not in sound the settings but in the accessibility settings menu, I just looked it up!

    I know this will sound strange but I do not have any music loaded on my iPads or use them for music playback at all. On my Android tablet I only have a couple audio files that I just use for testing every now and them.
    As for my phone….to make a phone call I have to flip it open!

    #90420
    Profile photo of Gordon
    Gordon
    Participant

    Oh Hi, Debby! Fancy meeting you here.

    It’s a mini 7″ Android that I bought just for playing mp3’s. (Not the same tablet that I use to run the mixer.) It stays on the little tablet shelf at upper left of the mixer. I don’t see anything in the sound settings or in the accessibility settings either, but I’ll keep looking. It’s apparently a stripped down or “light” version of Android.

    Anyway, that’s okay. I already have the system summed in the Ashly Protea speaker mgt now. I used to always run the system in stereo, but wanted to try mono for a while. The Protea is a permanent part of my upright mixer case now. I like using it because I was able to tweak my crossover settings, more so than I could on the powered speakers, and now the system sounds even better. (Most of the bass guitar notes are more even in level and everything sounds a bit more full and rich.) It seems the whole problem/solution was a blessing in disguise.

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