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Sound Reinforcement - Forums for Live Sound Professionals - Your Displayed Name Must Be Your Real Full Name To Post In The Live Sound Forums => LAB Lounge => Topic started by: Robert Lunceford on March 14, 2019, 08:38:42 PM

Title: Any Reason I shouldn't Do This?
Post by: Robert Lunceford on March 14, 2019, 08:38:42 PM
I am going to be running sound for a small combo (vox, piano, drums) in a space that has a house PA. There is not much flexibility or easy access with patching mic cables and accessing the mixer as it is in an audio closet.
There is a podium that has an XLR cable that I can access that feeds CH 1 of their Behringer XR18.

My plan is to bring in my QU PAC and use it to do the actual mixing.
I will take the main mix output of the QU PAC and feed that signal into a BSS AR133 active DI box, 40db pad engaged.
The DI out is connected to CH 1 of the XR18 via the podium mic cable.

I have tested this set up and it appears to work well. In my test system I was using a Soundcraft analog mixer in place of the XR18. Is there anything I am missing that might come back to bite me?



Title: Re: Any Reason I shouldn't Do This?
Post by: Rob Spence on March 14, 2019, 08:47:29 PM
I suggest a passive DI. All you need is a transformer to protect your mixer from theirs.



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Title: Re: Any Reason I shouldn't Do This?
Post by: Geert Friedhof on March 14, 2019, 09:45:17 PM
I suggest a passive DI. All you need is a transformer to protect your mixer from theirs.



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Why? Just use the phantom of the xr18, and be done with it... I think it's a solid plan.
Title: Re: Any Reason I shouldn't Do This?
Post by: Robert Lunceford on March 14, 2019, 10:50:49 PM
When I set up my test system I tested both a passive Whirlwnd Director and the active BSS DI. The signal was a bit hot with the Whirlwind. The only pad it has is for connecting to an amplifier output. This knocked down the signal level too much. The BSS on the 40db pad setting was just right. The podium mic is a condenser so the phantom is already engaged on that line.
Title: Re: Any Reason I shouldn't Do This?
Post by: Eric Snodgrass on March 15, 2019, 01:12:39 AM
Robert, I think your plan is solid. 
There's a certain multi-purpose room where I occasionally do gigs that only has a single XLR mic-level input in their booth that I can use to tie into their P.A. rack.  I use a Shure A15LA (http://www.shure.com/americas/products/accessories/microphones/microphone-problem-solvers/a15la-15-db-attenuator) -50db attenuator in line when I connect my mix rig to this input.  It works perfectly every time. 
Title: Re: Any Reason I shouldn't Do This?
Post by: Chris Grimshaw on March 15, 2019, 04:46:01 AM
The plan is okay, so long as you can make sure the venue's desk doesn't have any processing on that input.

It does also include an un-necessary round of analogue-to-digital-to-analogue conversion, plus padding levels only to boost them again, so I'd expect an improvement in sound quality from going direct from your desk to the PA, if possible.

Chris
Title: Re: Any Reason I shouldn't Do This?
Post by: Douglas R. Allen on March 15, 2019, 06:10:25 AM
The Non Clip input of the 1/4 inch combo jacks are rated at +21 dbu. I'd get a XLR to 1/4 inch tip,ring,sleeve adapter and go straight out of your mixer and into channel 1 line level input. Start with the gain down and adjust from there. Page 34 in their manual.   

https://media.music-group.com/media/PLM/data/docs/P0BI8/X-AIR-Series_M_EN.pdf

As an example.

 https://www.google.com/search?q=XLR+to+1/4+adaptor&client=firefox-b-1-d&source=lnms&tbm=isch&sa=X&ved=0ahUKEwj2rrfO84PhAhUko1kKHXWECK4Q_AUIDygC&biw=1920&bih=928

Keep it simple.

Douglas R. Allen
Title: Re: Any Reason I shouldn't Do This?
Post by: Stephen Swaffer on March 15, 2019, 12:37:59 PM
How's he gonna do that when he can't get to the mixer-which is why he is using the XLR in the first place?
Title: Re: Any Reason I shouldn't Do This?
Post by: Kevin_Tisdall on March 15, 2019, 03:20:26 PM
I am going to be running sound for a small combo (vox, piano, drums) in a space that has a house PA. There is not much flexibility or easy access with patching mic cables and accessing the mixer as it is in an audio closet.
There is a podium that has an XLR cable that I can access that feeds CH 1 of their Behringer XR18.

My plan is to bring in my QU PAC and use it to do the actual mixing.
I will take the main mix output of the QU PAC and feed that signal into a BSS AR133 active DI box, 40db pad engaged.
The DI out is connected to CH 1 of the XR18 via the podium mic cable.

I have tested this set up and it appears to work well. In my test system I was using a Soundcraft analog mixer in place of the XR18. Is there anything I am missing that might come back to bite me?



I've done the same thing before with a different combination of mixers.  (X32==>analog Mackie)  Similar issue - can't repatch but could get to the mixer controls.  Just make sure the XR18 input is bypassing any processing.  You may want to use what they have set up for output processing (eq/limiting) or not.   You may be able to bypass those as well.

--Kevin