ctsooner and tomic601,
I agree with both of you that subs outputting any bass in the 150 Hz range (I would even say any bass of 80 Hz or higher) is directional and can cause issues. I've experimented with the Debra amp's crossover filter control, adjustable from 10 to 220 Hz, and definitely notice the bass performance and sound staging suffer when crossed over too high.
My Magnepan 2.7QR panels are rated as producing bass down to 34 Hz +/- 3 dB. I think that's fairly accurate but have never measured them.
In my room, I've found a low low-pass filter setting works best and I normally have it set at 40 Hz. I realize theoretically that leaves an overlap between 34 and 40 Hz , since I run my panels full range, but it still sounds best to me.
All 4 subs are run as mono and none have their phase reversed; the Debra manual suggests reversing the polarity on 1 of the 4 subs progressively to verify the bass doesn't sound best in your room with the phase reversed on 1 of the subs. My setup sounded so amazingly good with all in-phase that I never even bothered with trying this.
I have absolutely no connection with Audio Kinesis but can honestly tell you that 'm thrilled with how well these dba systems actually provide true sota bass at a reasonable price.
You're probably thinking this dba solution sounds too good to be true. I completely understand this reaction since I was so skeptical when it was originally described to me that I almost didn't buy it. Thinking back to that time, it's a bit disconcerting how close I came to taking a pass on the Debra, due to cost and space concerns, and how fortunate I now feel that I decided to buy it.
It honestly works so well in my room and system that I can't think of any bass quality needing improvement. I do believe 4 Vandersteen Sub 9s would provide more bass than the Debra system but I'd really need to compare them to determine which produced better bass in my room.
Dbas are ideal bass systems for seamlessly integrating sota bass with any speakers, especially 'fast' panels. I don't think I'm ever going to need another bass system, even if I switch my main speakers in the future.
Tim
