Mijostyn wrote: "Duke I need you to define what you mean by a minimum phase system."
I probably shouldn’t have used that term, as it sounds like I’m talking about phase response. You can google the term "minimum phase system" if you want.
Instead of using the term I should have simply said something like this: At low frequencies, there is a correspondence between the frequency response and the in-room decay such that they track one another. When there is a frequency response peak, the corresponding decay time is longer. The correspondence is such that if we fix one, we simultaneously fix the other.
Misostyn again: "Duke is saying is that placing subs randomly throughout the room creates a situation that smooths out the frequency response throughout the room."
Just one minor point: I’m not really advocating RANDOM sub placement; I’m recommending DELIBERATELY ASYMMETRICAL and INTELLIGENT sub placement.
Mijostyn: "According to Earl Geddes... you want to keep your subs as far apart as possible and throw the fourth one away."
The four-sub configuration I use was Earl’s first-generation multisub-system. He subsequently wrote a program that can analyze the outputs of three subs and design custom digital equalization filters that will attain his goals without needing that fourth sub. The drawback is, if you move any of your subs or buy a new sub or change rooms, you need to have Earl redo the equalization in order to return to optimization.
Hleeid wrote: "Still looking for comparisons between the Swarm and DEBRA systems."
The only significant difference is the shape of the footprint: The Swarm units have a square footprint (12 inches by twelve inches), and the DEBRA has a rectangular footprint of approximately the same total area. The woofer is the same, the internal volume is virtually the same, and the port tuning frequency is the same. They use the same kind of long, pluggable port.
In the Swarm, the downfiring port is behind the woofer, and in the DEBRA the downfiring port is alongside the woofer. Hence the different footprints, but I don’t think there is any corresponding difference in performance. Jim thought a rectangular footprint looks better, and he has a much more artistic eye than I do. I sent the Swarm to Robert Greene of The Absolute Sound for his evaluation, which is why the Swarm rather than the DEBRA has been named in three Golden Ear awards and a Product of the Year award.
Duke
