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Cardioid Sub Array, Subwoofer Steering, HOW TO DO IT?

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Dan Richardson:
Tom Danley wrote on Sat, 24 April 2010 10:07
“Am I concerned about acoustic infinity the land where the posted computer models live, or, am I interested in what happens at a finite distance like 40-90 feet where the people are likely to be?”

Actually, I'm interested in what happens inside a club.

Got neighbor issues with a new all-ages all-volunteer DIY venue.
Subs are a pair of double 18s a side, and they sound wonderful.
They also sound wonderful in the neighbor's apartment, 50' from the backstage wall.

I'm wondering if the delayed array discussed here is likely to help,
or will the enclosure of the room negate the directionality?

Obviously, just trying it out would be best, but the PA is ground stacked.
Flying the tops would be distinctly non-trivial, and is out of the question for a test.
There are people here who actually know things, so I thought I'd ask.

Any opinions?

Adam Schaible:
I'm not one of the guys that knows something but I have been researching sound isolation techniques and I think while the CSA will reduce levels behind, depending on the size of the club, the reflected energy off of the walls may not be much down from the direct radition.

I think you might be better off adding another wall, staggered or even double stud and then using some sound isolation clips to re-do the ceiling in that area.  You'll probably get 10+db out of that, if you need more you could use quiet rock and/or mass loaded vinyl.  Also build your accoustic walls with studs 24" on center rather than 16" as the additional flex is desired.

Probably a thread swerve, but just model CSA with walls about the size of the club in mapp online - only problem is that it's 2 dimensional so even if the levels are reduced behind the array in the horizontal plane, I'm not sure how much the effect is negated when the vertical plane is taken into consideration.

Art Welter:
Dan Richardson wrote on Fri, 30 April 2010 10:56
Tom Danley wrote on Sat, 24 April 2010 10:07
“Am I concerned about acoustic infinity the land where the posted computer models live, or, am I interested in what happens at a finite distance like 40-90 feet where the people are likely to be?”

Actually, I'm interested in what happens inside a club.

Got neighbor issues with a new all-ages all-volunteer DIY venue.
Subs are a pair of double 18s a side, and they sound wonderful.
They also sound wonderful in the neighbor's apartment, 50' from the backstage wall.

I'm wondering if the delayed array discussed here is likely to help,
or will the enclosure of the room negate the directionality?

Obviously, just trying it out would be best, but the PA is ground stacked.
Flying the tops would be distinctly non-trivial, and is out of the question for a test.
There are people here who actually know things, so I thought I'd ask.

Any opinions?


If the LF in the neighbor's apartment is primarily through diaphragmatic transmission from the backstage wall, doors and windows, a cardioid pattern array could help. There are configurations that involve turning the top sub backwards, reversing its polarity, and adding delay to the bottom sub that would allow your stack to be the same footprint it is now.

However, if the LF is also exiting elsewhere (likely), from side walls, roof, windows,front door, etc. the rear reduction may not  be significant in the apartment.

Using an RTA, you may find the apartment has a narrow frequency band being excited, a deep notch at that frequency in your subs may cure the problem and have  minimal sonic effect in the club.

More minimal than being shut down due to noise complaints   .

Art Welter

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