Grant Bunter wrote:
I don't think DSP will solve the problem BTW.
I also don't think it will solve anything. But maybe I can move the problem around and use it to my advantage.
The sides of the room are the only places I want bass. Right now it's strong in the middle, medium on the sides, and dead in the two spots between.
The center opens to a hallway which carries sub bass throughout the whole house. Nobody ever hangs out in the middle; there's no seating there. Having the most bass here is my main issue.
If I can move the cancellations around with phase/time delay, I'll be more than happy. E/g weaker in the middle, stronger on the sides.
Heck, reversing polarity on one side might get me part way there lol.
Reversing polarity in one cab is simply going to cause cancellation across the entire band pass for the subs, so that's a no go.
Also, changing phase via DSP won't really alter the problem, in that, the physics of sound waves means regardless of how much you phase shift via delay, the wave still occurs.
Phase is frequency dependant, so you end up in a catch 22 unless the only frequency you try to address is that at the crossover point between subs and tops.
You also can't change the physics of sound, in this case, the fact that sub bass is omnidirectional.
It simply goes everywhere.
I don't think you're going to change the sub bass to being "only on the sides", or "not down the hall" due to this (but would be happy to hear you managed this, and how you did it).
I've had this problem for you trolling through my head all day.
The problem of cancellation due to inadequate separation can somewhat be addressed, by using DSP to high pass from say 50Hz. Why 50Hz? This is where the T18 starts to fall off anyway, but it will also reduce whatever cabin gain is happening below that point if you use a steep slope filter.
Kick drum thump is 50-80Hz. The lowest bass notes will still be heard via 1st harmonics.
It doesn't change the omnidirectional nature of sub bass, but it will reduce some of the longest travelling waves (due to frequency), reducing the effects in the hall.
This isn't something I would normally suggest, but yours seems a unique situation.
Certainly worth a try...