Sorry, I missed the comment on the
DSP I/O but there are some processors that may have sufficient physical inputs and outputs yet may not be able to provide the appropriate routing and/or processing so you might want to make sure what you have can be programmed to provide the routing and processing necessary. It does sound like you have the
power and physical space issues addressed.
Not knowing the space, my concern with
ground stacking is that with a 105' depth you could conceivably have a 20dB or greater difference in
level between the front seats and the rear seats. Add to that the '
power alley' from split subs getting the same signal and you might have the front middle seats 25-30dB higher in
level than some of the off-axis seats at the rear of the
house.
Since it was already mentioned, the VRX918SP can be flown using the VRX-AF
array frame, but it would apparently be pushed to provide 105dB to all seats in your room. If you went with the VRX918SP you might be better off to fly two together next to the center
array, that would minimize the '
power alley' effects, help even out their coverage of the seating and get some coupling, and thus additional output, from the two subs being together. The Yorkville LS800P seems to not have as low a LF response as the VRX918SPand is not flyable. The
Mackie SWA1801 also cannot be flown. It is actually difficult to compare the output of these devices since the specs are not real
clear on whether the numbers represent whole space or half space and the
Mackie SWA1801 specs actually state a "Maximum SPL @ 1m" of 129dB and then a "Peak Output @ 1m" of 135dB, the higher number may be intended to represent half space loading but it is not at all
clear.
Slightly off subject, with your existing R-H TRX mains you will likely be greatly on your own for the
system settings and tuning, don't forget to budget for any assistance or equipment you need for that.
