Originally Posted by Alan P
Hmmm...do you guys think the XV15s would have trouble keeping up? This is a good point and something I would like to know for sure.
already answered that adequately: yes, they'd keep up if they are placed closer.
Originally Posted by basshead81
Remember you loose 6db of output every 1m of distance that is added between the LP and Sub.
This isn't right though. You loose 6 dB each time you *double* the distance. (When performing dB SPL computations starting from a speaker's sensitivity, it's most often rated at 1 m; or when converting CEA-2010 data at 1m to data at 2m; so you subtract 6 dB when at 2 m, but it's not because you added one meter, it's because the distance is doubled).
So if there is 6 dB difference in the max output of the XV15 vs XV30 (not sure what the real numbers are), then placing the XV30 twice as far as the XV15 would be sufficient to compensate for the difference. If you were in an anechoic parking lot, of course.
In a room, things are harder to predict, although a nearfield sub sure would not have to work as hard as a sub on the front stage. So if you go with 2xXV30 + 2xXV15, placing the XV15s nearfield should be sufficient to ensure they're not the limiting factor in the setup.