| Re: Downfiring flanking subs ?? [message #75491 is a reply to message #75489] |
Sun, 10 February 2013 16:28   |
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Wayne Parham
Messages: 18783
Registered: January 2001
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Illuminati (33rd Degree) |
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| dheflin44 wrote on Sun, 10 February 2013 13:34 | I was planning on placing the flanking subs fairly tight in the front corners. I was hoping this would improve room coupling and also lessen the distance the mains needed to be from the front wall while maintaining the same relative spatial offset to the flanking subs. But you're saying it's better to have the flanking subs some distance into the room?
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Corner placement usually works pretty well, and you could then also put distributed subs in the opposing corners for modal smoothing at lower frequencies. But I think you'll probably want the subs acoustic center out about a foot or two from the corner. It depends on how far they are from the mains.
Think about what we're trying to do with flanking subs. The notch that's created by the reflection from the nearest boundaries happens at the frequency where the boundary is 1/4λ distant. That makes the reflection 1/2λ shifted, so it causes complete cancellation. Putting a sound source near the boundary "fills in" the hole, because neither the subs direct sound nor its reflection is 1/2λ from the mains.
As you reason through this, you'll understand that you can put the flanking subs right on the boundary and they'll mitigate the notch. In fact, that's probably the best approach in some cases, and corners are likely one of them. But remember that it is complex summing, and we're looking for dense interference so I tend to stay away from perfect multiples of 1/4λ. I'd rather be a little bit one side or the other, like 1/3λ or 2/3λ. This gives partial summing and tends to widen the frequency range where it's most effective.
One more thought, if you have corners available, have you considered constant directivity cornerhorns? I am assuming you don't have symmetrical corners or that one or both has an entryway or something. But if that's not the case and you have two good corners, I would suggest using constant directivity cornerhorns.
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