Re: Variable sound quality, JBL PRX rig
A few points...
The best way to make a PRX rig sound good it to run your mixer straight into the XLF subs. Engage the cross-over in the subs. Run the output of the subs into the tops. Run the tops in full range.
The XLF's cross-over at 90 Hz. This will work quite well with the 615's which should be able to pound nicely on the mid lows.
Putting the subs together in the center of the stage gives you a nicer coverage pattern than one sub per side in most rooms.
Using a single sub and single top, bring the volume up to a respectable level with some relatively thumpy music. Have someone listen to the sound out front with the XLF phase switch in each position to tell you which one sounds better. My guess would be to leave it in the "out" position.
Finally, as others have said, the PRX powered speakers CAN sound very good. It is difficult to make the system sound bad IME unless you do too much to it.
btw haven't heard from the OP.
