interesting output level shifts

i was doing a bit of work in Radial yesterday (imac, OS 10.2), and found that a particular loop, when added to the mix, suddenly created a drop in volume of ALL loops currently running. the only unusual characteristic i can think of that might have caused this was that this loop was much more full of bass frequencies, as compared to the others. i changed the global limiter & tube saturation parameters, and while this changed the relative sound of all the loops, it did nothing to alleviate the volume shift when punching this loop in and out.

on a separate but related note, i've notice some clicking and popping when some loops are turned on & off, especially on this file. thoughts?