Hello Mike,
If you're intuitive, you can probably guess what this word means just by looking at it. No? Maybe you're not so intuitive, after all. Intuitive means having the ability to know or understand something without any direct evidence or reasoning process. Your statement that "Now that I know what is going on it makes perfect sense and is indeed intuitive" defies logic; the very fact you required more information to fully understand the DBA concept proves it is NOT intuitive. I don't understand why you felt the need to rebut my statement that the DBA concept is counterintuitive, when it obviously is, but I suggest we just drop the whole subject and move on.
Thanks for explaining what you meant by having no rear wall, I get it now.
You stated: "I firmly believe that with any dipole speaker, Planar magnetic, ribbon or ESL you have to cross up higher at least at 100 Hz. This disqualifies a DBA. On the other hand my way of doing things may not work well with regular dynamic speakers. Pick your poison:)"
We seem to have different audio experiences and opinions but I think that's healthy since we both can benefit by discussing our differences. Even though you utilize a line source bass array system (LSBA) and I use a distributed bass array system (DBA), I believe it's a win-win scenario because we've both attained exceptionally good bass response performance in our rooms/systems along with also learning more about an alternative bass system solution.
In the spirit of benefiting from discussing our differences, I disagree with your statement that planar-magnetic dipole speakers need to use crossover frequencies of at least 100 Hz. I have planar-magnetic, dipole, 3-way Magnepan 2.7QR mains but they have decent bass extension, rated at 35 Hz +/- 3db. I run them full-range and usually cross them over to the 4 Swarm subs in the DBA at 40 Hz. This works very well in my system/room with the bass seamlessly integrated with my main speakers without any downside I'm aware of.
I think I understand your reasoning for suggesting using higher crossover frequencies on planar-magnetic, ribbon and electrostatic speakers. These speaker types don't typically have very deep bass extension and freeing both the speakers and the amp(s) driving them from the demanding requirements of reproducing deep bass are logically reasoned to improve the performance quality of both as a result.
This theory makes so much sense to me that I experimented with using crossover frequencies at various settings as high as 100 Hz, both with filtering out the low frequencies below the crossover setting and running the mains full-range. I stopped experimenting with higher crossover settings once I began perceiving the location of the subs at around 100 Hz and it began to have a negative affect on the normally very good stereo imaging of my mains.
I believe my system didn't gain the expected sound quality benefits of reducing the low frequency demands placed on my amps and speakers due to a couple of reasons. The first reason is the Magnepan 2.7QR mains I use are a 3-way design with rather large 625 square inch dipole bass sections that reproduce frequencies from their lower limit of 35 Hz to 650 Hz. But relieving these bass sections of reproducing the deepest bass frequencies in this range had no significant affect on the midrange and treble sections of these speakers. Also, any significant sound quality improvements in the bass sections' performance would be masked by the high quality bass reproduced by the Swarm bass system.
The second reason is that the D-Sonic class D mono-block amps I use for the mains deliver 1,200 watts into the Magnepans' fairly consistent 4 ohm loads. However, I still believe that systems using less powerful amps and speakers with simpler. less than 3-way, designs could realize significant overall sound quality improvements.
After extensive experimentation, I actually arrived at the opposite conclusion than you recommend, at least for my system. I thought my system sounded the best overall with the main speakers running full-range and the Swarm subs only becoming active on frequencies at or below a relatively deep 40 Hz and when the source content called for it.
I believe my system may perform even better overall with an even lower crossover frequency setting but 40 Hz is the lower limit on my sub amp/control unit.
My current thinking is that there are a number of good bass system solutions available, beginning with a pair of good quality subs, and that the choice of the optimum bass system, as well as its optimum configuration, is best determined on an individual basis.
Later,
Tim
