EAW UX8800...again

Shane Presley

Shane Presley

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Jan 12, 2011
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Ottawa, Ontario, Canada
www.bssproductions.com
So I set-up my first attempt at a cardiod sub array thanks to many of the suggestions here on the forum. I believe I was some what successful, although it probably could have been better executed by many of you I'm sure. There was a significant drop in sub activity on deck as opposed to out front, I didn't have a whole lot of time to tweak, but I was pleased none the less with the low end pattern out front, and the rear rejection on deck. Anyway to the point of my subject line, does anyone know if you can flip the polarity of an output on single mode on the UX. I was certain I am in single mode, selected SB1000z single, and could not find the phase invert option anywhere for the sub bands. What I ended up doing is feeding sub inputs C&D from A&B - making c the front facing subs, and d the rear facing subs and inverting the polarity. I know this is only using the "left" of the mains signal to drive the front, and the right to drive the rear, but I didn't have anything panned anyway, so I didn't think it woul dbe much of an issue...
If there isn't a polarity invert selection on the outputs of the UX, this would be another valuable software feature (EAW - hint hint)....
Other suggestions welcome. Btw , I know I'm going to get flamed for a ground stacked line array, I'll get over it.... the venue was a grass bowl, that probably rises 30' or more over 300 length from the front of the deck.. People sat where they liked the volume...
 

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Re: EAW UX8800...again

How close are the reversed subs to the stage? If you're only a foot or so away, that could account for the difference between your predicted pattern and what really happened.
 
Re: EAW UX8800...again

Hey Tim - yeah for sure they were too close to the stage, probably in the 8" area... I think it’s been said that about a sub length is preferred (3' ish). They festival organizers were a bit skittish about the "look of it", but understood the benefit, and they are accommodating. I'll probably try them end fire next year and see what I get to pretty up the front of the deck instead... None the less it was a great first try, and I experienced some success in my books. When I was playing music at a decent volume, I could step up from the ground through the sub alley, and easily drop 6-10 db of low end program as soon as I hit the deck... There was some increased coupling stage center, but minor in comparison to what was coming out front.
 
Re: EAW UX8800...again

Shane,

Those "tunnel" tents can also act as strange reflectors. We did one festival that had the green room on the area behind the stage under the tent, and every word said backstage was clearly audible onstage, even over the monitors. In addition, the FOH stacks that were outside the tent, excited a harmonic series under the tent. The tent would have clearly played havoc with any predictions.

I am not sure what the answer is, but if I ever had to be the system engineer of a show with one of those, I would be very careful about checking any changes, both inside and outside of the tent.
 
Re: EAW UX8800...again

Helge Dr. Bentsen said:
I just thought of one thing, I'm not sure if it can do a array with rear facing boxes, i've only used it for front facing arrays aka end-fire.
Click to expand...

That's what I was thinking... Quick question, what would be a " hardwire" solution for inv polarity... Reversing pos for neg on the amps yes? Also I use lab g fp10k amps... I assume I could rev polarity using the nl60b controller?
More testing to do... So little time
 
Re: EAW UX8800...again

Or a simple polarity reversal cable from the ux to the amp. Make it long and yellow so noone misses it if it's in use.

I have seen a polarity reversal button in pilot but suspect that this was some software revisions ago. And I don't have my computer nearby so I can't have a look at the software either.
 
Re: EAW UX8800...again

Helge Dr. Bentsen said:
Or a simple polarity reversal cable from the ux to the amp. Make it long and yellow so noone misses it if it's in use.

I have seen a polarity reversal button in pilot but suspect that this was some software revisions ago. And I don't have my computer nearby so I can't have a look at the software either.
Click to expand...


The polarity butotn is there, but it's on the inputs... which doesn't help when you're trying to do example
output 3 (sub right) - forward facing
output 4 (sub right) - rear facing (inv pol)

output 7 (sub left) - forward facing
output 8 (sub left) - rear facing (inv pol)

What I ended up doing was

input c - (sub left and right forward facing)
input d - inv pol ( sub left and right rear facing)

I think I'll make some short xlr (pin 2/3 swap) in yellow like you say between the Ux and the amp, and do it that way - keep the processor out of the loop.

My other pet peeve at the moment is having to use 4 "Y cables" to feed two lab 10K ch a+b the same signal and c+d
 
Re: EAW UX8800...again

If you are in system processor mode, select one of the output channels, then go to level in the menu and use left-right joystick to select polarity submenu and turn the wheel, surely polarity changes on that output?
 
Re: EAW UX8800...again

Greyboxes doesn't load in system mode afaik.


What you could do in single mode, is run the subs in mono and feed them from tow inputs, let's say c and d. Sum both physical inputs to mono by assigning them both to input c and d, run c as front box and d as rear box, and invert polarity on the input.

You are of course aware that input a to d doesn't have anything in common with the actual physical inputs :)
 
Re: EAW UX8800...again

Helge Dr. Bentsen said:
. Sum both physical inputs to mono by assigning them both to input c and d, run c as front box and d as rear box, and invert polarity on the input.
Click to expand...

That's pretty much what I did...

I have used the cardiod portion of the pilot software, which is what brough tme here in the first place(trying the configuration). The only thing I didn't notice in the softwrae ( which is pretty clear in the article and in the diagram) is that there are no REAR facing subs. I'm going to try forward facing only on my next attempt, using the cardiod section and seeing what kind of results I'll be getting. I plotted it yesterday, but I'm going to work with it more in the computer and out in the real world soon... Thanks for the great input, I find alot of this black art stuff is still not talked about and I'd like to improve my results in the field. Thanks all
 
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