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[James Heyser]

I am currently running four of these with four KF650's.  I just ordered the UX8800.  I have had mixed results with these, and have not used them enough to notice any clear patterns.

A few questions I had:

I was considering another set of four.  I see them in quad configurations more often than pairs.  Will this simply add a few decibels, or are there other significant advantages?

Any crossover, compression, or EQ techniques that have helped you get higher quality sound or more output?

I've read some critical reviews of these on PSW/LAB, but they're what I've got, so please limit your replies to tips on how I can better use what I have, not what I SHOULD have gotten!  ;-)

[Steve Ferreira]

http://www.eaw.com/info/EAW/Processor_Settings/Current_Products/Subwoofer_PROCS_rev2.pdf

[James Heyser]

http://www.eaw.com/info/EAW/Processor_Settings/Current_Products/Subwoofer_PROCS_rev2.pdf

Thanks Steve, I should have mentioned that I've been using the manufacturer processor specs, at least with my DR260.  I'm sure I'll notice improvement with the UX8800.  I was considering either lowering the high pass or having overlap with the tops, also hoping for insight about configurations (2x2, 1x4, and 2x4) and even variations in how to stack them.

I haven't had to use them enough to do a lot of trial and error experimentation (I don't generally have time to do that at a specific gig, I just try different arrangements from gig to gig), but I was hoping to get there faster with some advice.

[Justin Bartlett]

I'm not an expert by any means; one of the systems at my church has a single pair of these, and they're...let's just say ample...for the room (a decent-sized gym).

Anyway my understanding is that when you add cabinets to horn-loaded subs like these, you get several benefits:

1.  Assuming power per cabinet is constant, you get a 6dB output increase each time you double the number of cabinets in a given cluster.

2.  Adding cabinets to a cluster increases the effective size of the opening of the horn (due to coupling), thus lowering the bottom frequency at which the horn is effective/efficient.

3.  You also get something of an increase in directionality (which varies with frequency) when using clustered subs.  That's usually a positive, to a point.

That's pretty much the limit of my knowledge; if anyone else has *real* expertise I'd be interested in learning more myself.

[Justin Bartlett]

One other thing - it's my understanding that these cabinets were really designed to be used in clusters of at least four.  Obviously mine aren't used that way, since we only have two, but that's what I've been told.

[John Chiara]

Thanks Steve, I should have mentioned that I've been using the manufacturer processor specs, at least with my DR260.  I'm sure I'll notice improvement with the UX8800. 

The UX8800 isn't going to have an effect on the sub performance.

[Ivan Beaver]

Anyway my understanding is that when you add cabinets to horn-loaded subs like these, you get several benefits:

1.  Assuming power per cabinet is constant, you get a 6dB output increase each time you double the number of cabinets in a given cluster.

2.  Adding cabinets to a cluster increases the effective size of the opening of the horn (due to coupling), thus lowering the bottom frequency at which the horn is effective/efficient.

3.  You also get something of an increase in directionality (which varies with frequency) when using clustered subs.  That's usually a positive, to a point.

That's pretty much the limit of my knowledge; if anyone else has *real* expertise I'd be interested in learning more myself.

If you keep the power constant-then you will get around a 3dB increase in sensitivity.  When you double the power-you will get another 3dB.  So if you keep the voltage (not power) the same-you will get the 6dB increase.

You will get a lowering of the freq response when you cluster them together. However it is not as much as many people think.  What you do get is a larger mouth area-which changes the impedance loading and the ripples in the response (due to to small of a mouth area) are reduced.  So the overall response down low is much smoother-which can make it sound like it has more bass.

You do get additional forward directivity due to the physical size of the "array".

[Bennett Prescott]

The UX8800 isn't going to have an effect on the sub performance.

It will if the EQ, protective HPF, and limiters weren't correct.

[Wichak Chanmuang]

I would not call my advice as tips, but proper use.  First, make sure your amplifier can drive this sub not below 4 ohm load at least 1.5 - 2x its rating power (800 w/ driver) Second, ground-stack only!!, side by side or top on each other in order to create a horn mouth shape. Third, put the right amount of delay to your 650. (around 5-8 ms)
Since you only run 4 KF650, no need to have another 4 BH760 if you do it right..

[Helge A Bentsen]

Be aware that when you set up your rig with a ux8800, you'll need to measure the correct amount of delay on the 650s, because a ux8800 has different input to output processing times on different greyboxes.

[James Heyser]

I would not call my advice as tips, but proper use.  First, make sure your amplifier can drive this sub not below 4 ohm load at least 1.5 - 2x its rating power (800 w/ driver) Second, ground-stack only!!, side by side or top on each other in order to create a horn mouth shape. Third, put the right amount of delay to your 650. (around 5-8 ms)
Since you only run 4 KF650, no need to have another 4 BH760 if you do it right..

I see I should have included a lot more information about my system.  They're adequately powered (Crown IT4000, 2000 watts per cab @ 4 ohms).  I've programmed the delay as well, and my plan was to stack them as in the pic I'm attaching.  I'm curious how that's going to affect the coverage pattern, if anyone has any feedback with orienting them in this configuration as pictured or the same arrangement on it's side, please chime in!

I prefer to spread my subs out for live music (two to a side), for DJ's I've tried a cluster of four.  But comparing sub output for DJ's versus live is useless.  I'm wondering if anyone has experience with the output improvement over a cluster of four versus two pair.  Also, if I am using two pair, and I arrange them to form a single "horn shape", am I better off stacking or side by side?  I understand the basic functions and techniques (power ratings, time alignment, EQ & crossover) but I don't know how this will affect the coverage pattern. 

As for their capacity, I agree, even two of them has been more than adequate for some applications, but for reggae and DJ music I was thinking four more might pay off.  Also, eventually I may upgrade the tops.

[Justin Bartlett]

I see I should have included a lot more information about my system.  They're adequately powered (Crown IT4000, 2000 watts per cab @ 4 ohms).  I've programmed the delay as well, and my plan was to stack them as in the pic I'm attaching.  I'm curious how that's going to affect the coverage pattern, if anyone has any feedback with orienting them in this configuration as pictured or the same arrangement on it's side, please chime in!

I prefer to spread my subs out for live music (two to a side), for DJ's I've tried a cluster of four.  But comparing sub output for DJ's versus live is useless.  I'm wondering if anyone has experience with the output improvement over a cluster of four versus two pair.  Also, if I am using two pair, and I arrange them to form a single "horn shape", am I better off stacking or side by side?  I understand the basic functions and techniques (power ratings, time alignment, EQ & crossover) but I don't know how this will affect the coverage pattern. 

As for their capacity, I agree, even two of them has been more than adequate for some applications, but for reggae and DJ music I was thinking four more might pay off.  Also, eventually I may upgrade the tops.

Based on my (limited) knowledge, I'd say what you have pictured would work great for indoor shows; I think it's more or less how they were designed to be used.

For outdoor shows you might be better off lining all of them up across the front of the stage one-high; otherwise you get the classic coverage issues throughout your coverage area:  power alley down the middle, patterns of addition and cancellation at different frequencies elsewhere.  That wouldn't really be any different than what you're experiencing with 2 per side though.

[Wichak Chanmuang]

Ok.. Got your point...   From my experiences, If you have only 4, you'd better do it L-R as your 650.. The differences of Horn shape or side by side is not much.. But whenever you have 8 of them you have a lot of patterns to play with...  and it's another story of output!!!

[David Gunness]

One other thing - it's my understanding that these cabinets were really designed to be used in clusters of at least four.  Obviously mine aren't used that way, since we only have two, but that's what I've been told.

The design was based on a block of four, but they work fine one at a time or two at a time.  Using fewer than four does not change the shape of the response, so the same processor settings will work no matter how you stack them.

Dave Gunness
(designer of BH760)

[Dave Gunnell]

Hi James:

I have the same system you do--KF650z over BH760 subs.  I was an early adopter of the BH760, and EAW inadvertently (I think) dropped one of the original PEQ filters when they put together their latest subwoofer processor sheet.  The additional filter (originally "PEQ2") is centered at 74.3 Hz, -5.0 dB, Q=1.6.  The other two filters (at 35 Hz and 177 Hz) remain the same.  In my opinion the sub does not sound right without this filter.

When I bought my UX8800 I measured the BH760 transfer function through the UX (with Smaart) and compared it to the previous settings I had in my XTA DP226, and I found I still needed to add the 74.3 Hz filter to get a similar processing curve for the sub.

I'd be interested to hear your feedback on the system with the additional filter applied.

Best,

Dave Gunnell

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