StuartOsborne Contributor - Level 2 2018-10-12

2018-10-12

XR18 - running mono on the mains

We usually run our mains stereo but this weekend we'll be playing a club with built in front of house. It's a small place with a small PA and I have not seen their setup yet but rumor on the street is they have a single XLR input to the PA.

I have only the keyboard player running stereo but I understand how to address that. It's the output that I wanted to ask about. After getting my keyboard player set up mono, should I simply pan the balance on LR channel to -100 and connect L out to the house system?

Appreciate any advice! Thanks...

Stu-

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Contributor - Level 2

Re: XR18 - running mono on the mains

I bought one of these for this very situation...

https://www.amazon.com/gp/product/B000KGYAYQ

I use a 1/4in stereo to L/R mono cable to patch the XR's headphone out into 2 channels of this little mixer. Then I can go from the mixer's output into any mono system I want.
Contributor - Level 2

Re: XR18 - running mono on the mains

As the Rane article outlines, attempting to sum a stereo source to mono simply by shorting the outputs together is a really bad idea. To do this properly, you need a mono summing box or cable that uses resistors to prevent the outputs from driving each other as if they were inputs. I've blogged about this extensively here:

Balanced mono summing: http://silentsky.net/wordpress/archives/863

Unbalanced mono summing: http://silentsky.net/wordpress/archives/624
Contributor - Level 2

Re: XR18 - running mono on the mains

Stuart Osborne;153531 wrote:
We usually run our mains stereo but this weekend we'll be playing a club with built in front of house. It's a small place with a small PA and I have not seen their setup yet but rumor on the street is they have a single XLR input to the PA.

I have only the keyboard player running stereo but I understand how to address that. It's the output that I wanted to ask about. After getting my keyboard player set up mono, should I simply pan the balance on LR channel to -100 and connect L out to the house system?

Appreciate any advice! Thanks...



Stu-

I never run stereo on a live show. If someone is on the extream right of stage they won't here the whole mix. You can come out left or right and Pan until you get the center sound. You can also just run out of Left and then go from Left main or sub to right main or sub. When I use Ultran net I run every thing out of channel 1. I have run Ultrnet on channel 1 and 2 with 1 being left Subs and Main and Channel 2 for Right sub and mains
Greg Bouten
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Contributor - Level 2

Re: XR18 - running mono on the mains

I've done theatrical productions with a mono PA and a green room fed from the Left and Right mains, respectively. This gives the green room an exact copy of the house mix without a splitter.

Pan everything center, and call it good. Any drop in level compared to "true" mono will be accounted for automatically by an active engineer.

Underscoring was from the vendors' official proprietary phone app through a stereo->mono mixing DI at the FOH position, feeding an XLR snake return that was then patched to an XR input just offstage.

My only true stereo source at the XR itself was the USB jukebox that I built into the rack. I ended up routing it to AUX6, just for the mono mix, then analog-patching that back to an input. Not ideal, but it worked. If I had the time, I could have mixed all of those tracks in Audacity into mono files and then used the USB feed directly.

Onstage fill monitors were fed from AUX1 and AUX2.
Contributor - Level 2

The solution and the gig....

Should have checked back in about this! I ended up using an Aux channel and it worked just fine. The venue is very interesting indeed. There is an elevated stage about 4 feet high in the middle of this very elongated bar/pub, seats about a hundred. The stage could only house our drummer w/ small kit and keyboard player. Bass (me), guitar and vox were in front of the stage looking at their ankles. Their inhouse PA has a single XLR input on the stage and feeds many speakers placed throughout the bar - some in the ceiling, some behind the bar. So we had PA in front of us, over top of us and behind us, all around us - very strange indeed. But, it worked. I brought a small powered sub and two small powered monitors - one for the stage and one for the floor. It could have been the quietest gig this rock band has ever played but they hired us back, so we did something right!

To get started, I set up a quick mix on Aux 5. 5 vox mics, 1 kick drum, 1 bass running direct only, 1 guitar mic, 2 keys. I had to set up FX as all my Aux channels were dry. I did this while everyone was working the stage. Once I was pretty confident, I ran up the two floor monitors and sub. Levels were pretty low. It was a bit interesting not visually seeing the house PA equipment, no clue what I was plugged into. So, I VERY SLOWLY ran up Aux 5 fader with my iPhone connected to Aux in. To my sheer delight, I got a great, strong, clear signal throughout the bar. Backed off the slider on Aux 5, then got levels set on all instrument/vox inputs to match Aux in, crossed my fingers and let it rip. Once again slowly up on the slider - no feedback. Tested everything and had a danged good mix right off the bat. Adjusted a couple of things and proceeded to a have a great night.

We've had the XR18 for a couple of years now. I'm still no sound man but I sweat it out a lot less when it comes to new venues or stage setups. It's just too easy on this thing! Thanks for all of the suggestions.
Contributor - Level 2

Re: XR18 - running mono on the mains

Glad it worked!

I remember doing another theatrical gig with the Aux outs. This venue had two PA systems:
- Ceiling wash over the entire room, covered stage and audience equally
- Audience only, also in the ceiling

So I ran the wash from Aux1, playing music and sound effects only, and the audience PA from LR, playing mics only. Let the music and voices mix acoustically, coming from their different speakers. That worked pretty well too: set up the routing, balance the masters, then leave the masters alone and mix on the channel faders (or DCA's) as if it were one system.