sub placement theory

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nick mineau
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Joined: Fri Sep 02, 2016 8:56 am

sub placement theory

#1 Post by nick mineau »

I have gone threw most of the info on subwoofer placement I could find. It has been very valuable w horns, coupling and such.
however one thing is still not clear to me. I played w modeling and cant see why when you get to an spacing of more then 2 wavelengths at the lowest frequency your subs play (56ft for 40ish hz)
does it become acceptable to run l/r subs? Thanks in advance.

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Bill Fitzmaurice
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Re: sub placement theory

#2 Post by Bill Fitzmaurice »

Use this to see what happens. You'll need Adobe flashplayer.
http://www.falstad.com/wavebox/

With two point sources placed tight together the wave is uniform. When separated you get high intensity radiation on the left, right and center (the power alley) and severe cancellation between the left and right wave fronts and the center wave front. As you make the separation wider the intensity of the wave fronts is reduced and there are many more of them, making the power alley effect far less noticeable. Next use this to see what happens to those individual waves as the distance from the source is increased:
http://www.acoustics.salford.ac.uk/fesc ... fract4.php

Close to the source the individual waves are distinct, but with sufficient distance they become one. If your room is large enough that you can separate the subs by 50 feet or more it's probably large enough to place the audience far enough out for wave front integration to occur.

himhimself
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Re: sub placement theory

#3 Post by himhimself »

Cool links. Thanks, Bill
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ACUA
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Re: sub placement theory

#4 Post by ACUA »

I have had a few situations where splitting my subs has been advantageous. Some smaller eccentric venues allowed me to power alley and get high energy on the dance floor while somewhat canceling allong the walls of the venue. This picture was one of those places where I did split the subs a little bit. And I had all the power in the world where I wanted it and back where the chairs were it was somewhat attenuated. When I couples the subs together in this venue the roof rattled “tin roof” real bad at the location of the subs. the rattle was somewhat mitigated in the shown configuration. I do however couple the subs together whenever possible (most of the time)or at least I try that first when setting up.
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nick mineau
Posts: 48
Joined: Fri Sep 02, 2016 8:56 am

Re: sub placement theory

#5 Post by nick mineau »

almost all my shows are outdoors. but I get what your saying bill . thanks very much for explaining it. I normally just center couple subs.
but was starting to look at putting the tops on the subs for the benefit of not needing stands or staging. thanks :)

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