Two Subs? Set up question...

[huskies90]

Guy in our band just bought a second sub. My question is for best results should the two identical QSC powered subs be placed in the center of the stage up against each other, split with one on each side of the stage under the mains or it doesn't matter either will be fine...??

[baba]

Ideally, center clustered to reduce comb filtering and cancellation. Without a raised stage this can be difficult, so you'll often see left/right configs. Another option is clustered in a corner....I think the rule is more than two feet from wall, but less than 7..??

[huskies90]

So even if they are are identical I could still have comb filtering and cancelation (not really sure what that means). And is that signifcant 'cause it is easier to stack the mains on them? Any place that we would use two subs would have a raised stage so centering them is not a problem.

I had heard that putting them together and doubling both the power and cone area makes a difference and that you lose that when they are separated...

[JimmyM]

Cluster in center is best, cluster to side will also work.

[baba]

Originally Posted by huskies90

So even if they are are identical I could still have comb filtering and cancelation (not really sure what that means). And is that signifcant 'cause it is easier to stack the mains on them?

Yes, definitely and yes. Cluster them in the middle.

[JimmyM]

Originally Posted by huskies90

So even if they are are identical I could still have comb filtering and cancelation (not really sure what that means). And is that signifcant 'cause it is easier to stack the mains on them? Any place that we would use two subs would have a raised stage so centering them is not a problem.

I had heard that putting them together and doubling both the power and cone area makes a difference and that you lose that when they are separated...

Comb filtering is where the signals bounce off of each other and create cancellation zones. As you walk around the crowd and the bass takes your head off in one part of the audience while you can't hear it at all 5 ft. away from where you were standing, that's a result of comb filtering creating power alleys and cancellation zones. I forget the formula, but there's a certain distance that subs have to be apart to keep them from combing. You can Google it and find tons of reading material about it.

Also, if the room is pretty live, it can also create cancellation zones from bouncing off the walls. But clustering the subs can help and at least remove one problem from the equation.

[Zooberwerx]

Originally Posted by JimmyM

Cluster in center is best, cluster to side will also work.

+1. We keep ours center stage, sometimes with a monitor between. The enclosures have relatively low profiles so its not too obtrusive.

Riis

[TimmyP]

To eliminate the Power Alley, the subs need to be together, or more than 40' apart.

Subs should be within 2' of any boundaries (floor, wall, ceiling) or at least 8' away from any boundaries, otherwise there will be a cancellation within the bandwidth of interest.