Dual vs single sub

"The best you can hope to do in any enclosed space approximating a livable room is to control primary reflections and since they have the most energy that represents 90% of the battle."

I disagree with this statement as far as the bass region goes.

From a perceptual standpoint, speakers + room = a minimum phase system at low frequencies (according to Toole and Geddes and Welti, among others), which means that the ungated in-room frequency response is what matters. Focusing on the first reflections is at least paying attention to room interaction, but imo it’s not focusing on solving the problem that matters the most to the ears in the bass region.

"Putting subs all over the room simply creates more primary reflections."

Primary reflections in the bass region are not the primary problem that needs solving. But having many primary reflections contributes to solving the primary problem.

"... room control [EQ?] frequently has to correct troughs of up to 10 db and more..."

With a decent distributed bass array, you will not begin to have troughs of 10 dB or more. If your technique results in troughs of 10 dB or more then it is not solving the problems that matter. I don’t claim my customers will necessarily get plus or minus 3 dB in-room in the bass region, but many of them have reported that.

"Oh, by the way Duke, I am not trying to sell anything."

Okay. Maybe I’m missing something. How is that relevant? Please clarify because I don’t want to jump to conclusions.

Thanks.

Duke

Several posts above I wrote: "your four subs only approximate a line source; each sub still behaves as an omnidirectional point source."

Presumably in response, mijostyn wrote: "4 subs at 4 foot intervals with the outer two in corners does not approximate a linear array. It is most definitely a linear array up to 125 Hz or so."

Okay, but a line array is not a line source. A line array *approximates* a line source, which is what I said.

"If you review the acoustical properties of linear arrays you will note that they throw very little acoustic energy off their ends almost totally killing any refection off the side walls of the room

Imo their behavior at their ends isn't a potential issue; their behavior out in front of their ends (along the sidewalls, in this case) is a potential issue.

I know how to model line arrays. The spacing you used is not optimal. I can explain why if you are interested.  Because its propagation is not perfectly perpendicular to the line, your array will have increasing sidewall interaction with distance. I’m not saying that’s a fatal flaw, only that it happens.

"No other array does this in any dimension."

A planar array does this in two dimensions. In fact, I think a planar array would make more sense than a line array for your situation, given that your room doesn’t have a back wall (which imo offers you a unique opportunity). Again, I can explain if you are interested.

Duke