Originally Posted by Gooddoc
The only issue with running all on the same amp is the inability to level match, although not sure that is an issue if the 4 subs are in each corner??
, what are your thoughts on potential issues trying to calibrate 3 slaves and a master at the listening positions, each in their own corner? Thanks.
You would want 2 powered units for 4 corner positions. As much as I and most other calibrators have tried, I have yet to see a tangible benefit to sending a different signal to subwoofers that are both at the front wall or in front corners. Same for a pair at the rear of the room, or pairs at similar front-back depth on the side walls. Some day I could see separate signals useful if using a tool like Dirac Unison in rooms that aren't structurally symmetrical left-right, such as where one wall has a concrete foundation behind it, and the other is drywall studs to a utility closet or other room, but typically the different interaction vs placement with the boundaries is desired to create a complimentary blend. The whole conceptual benefit of placing a pair of subs in front corners or 1/4 points is based on sending them identical signals. It falls apart if you feed them differently!
I strongly recommend separate signals for the front and rear grouping of subs, with a pair front and rear being a great solution for most rooms. In most cases all that is needed is an appropriate delay applied to the rear group of subs. On rare occasion you might back down the level of the rear subs if they are super close to your seats. In the majority of cases this creates a great platform to deliver great bass to the listening area empirically through measurements and iterative adjustments. The hardest part is taking care to label measurements so you can look back at what you measured. The current versions of our amplifiers even have a delay knob to facilitate this exact configuration if the surround processor is happier or not capable of applying the delay. In small room acoustics, subwoofers operate on total power put into the room. It's near impossible to level match subs with widely varying frequency responses, as you can only average or pick a frequency. With identical subwoofers it is much better to "gain match," where each sub is contributing equally, and thereby one won't run out of gas with the others not contributing equally. A handful of measurements moving your current subs into position could give high confidence or show limitations in such a solution. So long as you are not sitting at the midpoint front-back in the room, and both locations don't produce coincident troughs in the response, you should be good with the 4 corner approach.
You could alternately pay Keith Yates Design for their BassCAMP optimization, but the accuracy is based on the accuracy of the model of the room. It is highly accurate in rooms of their design with well known acoustic properties, with uncertainty increasing as the acoustic properties of the boundaries become less well known or more variable.
The SubMersive HP and F2 packages are still current for a reason, and they will continue on well into the future. The F2 package (dimension drawings here
) is the smallest footprint with the trade off of a 35.5" height. The chamfered rear corners also allow it to be tucked tight in a corner if space allows.
I haven't made formal announcements yet, but I did just finish up two new 18" packages which pack the same performance of the F18 into either a much shallower 12" deep package, or smaller front profile of 20" square. I posted some info on these in Art Sonneborn's thread where the first of the DS18-20 was installed
. The first of the shallow DS18-12 were just delivered to AVS member Lasalle's home for his "LOGE" project