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[John B. Miller]

Adam Schaible wrote on Tue, 29 June 2010 22:54

It should probably be stated that these charts are created without considering any boundaries.  As it stands, the prediction software only works in 2d anyway - 3 dimensional prediction is amazingly intense and at best is a guess due to varying objects in space as well as different degree's of rigidity in surfaces, people in the venue, etc. In any case, center cluster is likely to be superior - but it's really not a more or less energy, it's just where IS the energy. Another thing about center cluster, you could look at the second chart at 40hz, 80hz, etc and it would look the same.  The first (split l/r) would be different. I'd say the short answer to the original question is something like "always unless you can't for a good reason".

You're absolutely right, Adam. The response does change somewhat at different fequencies, but not that much. And boundaries do definitely change the whole ballgame. Generally though, the more energy you can direct at your audience and NOT at the walls, the better, and the fewer sources, the better.

[John B. Miller]

Here's the plot of the LR deployment with rigid "walls".

[John B. Miller]

And the tight centre cluster with walls...

[(BJ) Benjamin Fisher]

Lots of good stuff guys...some of it is a bit over my head but I think my original question has been answered. I've never tried to cluster my subs before and most of my gigs wouldn't really allow for it due to space issues but I will give it a shot for this particular gig coming up next. Or atleast if the stage permits.

[Adam Schaible]

If you have a lake nearby - this could be an interesting way to visualize it differently.

Toss two stones in the lake at the same time in different areas - but not too far apart.  When the waves hit each other, their combination causes the amplitude of the wave to increase, decrease, or stay the same.  This will not be consistent everywhere in the pond - some places the waves will increase each other, other places they will decrease each other.  The one interesting thing is that once the waves pass through each other, they continue on along as if nothing at all happened.  "Destructive interference" only exists in certain area's - it's actually pretty cool to look at.  If you can get large bands  in the water you will see that at some point their interaction will make no wave at all, in others it will create a big wave (relative to the size of the wave without any interaction).


One thing to remember is that the waves created in the example above typically only travel in two directions.  Since sound waves travel through air, and air exists in all 3 dimensions - the resulting interactions are much more difficult to visualize - however for some reason not much time is spent visualizing the vertical domain.

Some will say it doesn't matter but I disagree - it matters just as much, it's just that most of the time we can't do much about it - just food for thought.

[John Chiara]

Not to change the subject....but how did this rig and setup sound? Capacity?

John

[John B. Miller]

John Chiara wrote on Wed, 30 June 2010 00:28

Not to change the subject....but how did this rig and setup sound? Capacity? John

What rig are you referring to?

[Art Welter]

John B. Miller wrote on Wed, 30 June 2010 13:16

John Chiara wrote on Wed, 30 June 2010 00:28 Not to change the subject....but how did this rig and setup sound? Capacity? John What rig are you referring to?

"John A. Chiara aka. Blind Johnny".

[Don Davis]

Not my intention to take away from the OP and if this needs to be a new thread let me know and I'll repost. We did this event in a park this past weekend and I really wanted to center cluster after reading so much about on this forum but the church's sound guy was resistant. Do you think it would be beneficial in this park set up? All four down front on the lawn?
tops - (4) SRX 712's bi-amped w/ 2 - crown MA1200s per side
subs - (4) SR4718X (2 per side) w/ 1 crown MA2400 per side

Its a big area but the crowd was around 300. We will be returning there later this summer for another event.
Thanks!

[Mike Christy]

Don Davis wrote on Wed, 30 June 2010 18:22

Not my intention to take away from the OP and if this needs to be a new thread let me know and I'll repost. We did this event in a park this past weekend and I really wanted to center cluster after reading so much about on this forum but the church's sound guy was resistant. Do you think it would be beneficial in this park set up? All four down front on the lawn? tops - (4) SRX 712's bi-amped w/ 2 - crown MA1200s per side subs - (4) SR4718X (2 per side) w/ 1 crown MA2400 per side Its a big area but the crowd was around 300. We will be returning there later this summer for another event. Thanks!

Yes, you would have gotten the benefit of the hard boundary behind the subs (+3db) and another increase with the coupling of the other cabinets (+12db). It's a no brainer.

In addition, I would have used one set of mains on each side of the band, closer in, and if you did need additional coverage, set up the other set adjacent and splayed so the HF patterns do not overlap.

Just my thoughts...
Mike