Just thought I would share my experience and maybe generate some discussion. I run a pair of Ken Kriesal DXD808 subwoofers. When I first got them years ago, I was using an Anthem receiver with one sub output and later a multichannel DAC, again with a singular sub output. So i simply daisy chained them together and stacked them in one corner. Recently read about spacing them out for more even room response. Did that initially after I got the XMC-2 and simply ran off the centre sub channel.
But decided to swap them to the front instead of rear corners and with shorter cable runs, able to connect them to L/R sub outputs instead and finally got round to running Dirac again over the weekend. And the results are much better overall.
The sound image is razor sharp. Timing is crisp. Sound stage despite assymetric room is the most even I have heard. My thinking is although the subs are running as one channel, Dirac did calibrate them separately and aligned the phase/time accordingly (i noticed in real time the differences in the impulse response from each sub due to different wall reinforcement). I read in earlier threads that one should calibrate dual subs as one single channel. Wonder what your experiences are?
It's a bit difficult to explain without visuals, so you might want to go to: Finding Subwoofer and look at the second post which is perpetually the most current arrangement. It has been altered a number of times in the last year, some of which is demonstrated by comparing the beginning of the thread to the most recent.
With "stereo pairs" of pairs of subs there is a dip from 60-70Hz that's pretty deep, but is smoothed out very well with a sub in the back of the room. The stereo pairs thing is a yes it is, but no it's not, kind of situation. Each front has two subs that are used as extra woofers. So in that sense it's truly stereo. But, because the Fronts are setup as Large in the processor, and because three of the five subs are grouped into a LFE Group and connected to the Center Sub output setup as LFE, the Bass Management sends the Small bass to the Fronts for all speakers setup as Small.
So far, that's my experience. But it can change based upon proven performance gains.
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