I ran some preliminary sweeps to measure the response of the preamp and found that the subwoofer output is passing signals way beyond the 100hz cutoff.Its flat as a board from 10hz up to 100hz (I'm very pleased with the response) but continues to produce frequencies beyond the xover point? Just wondering about this. I should be 24db down @ 200hz.

These may be silly questions, but are you basing the 100Hz cutoff on the crossover settings for some of your speakers? If so, are you taking into account the possibility of a .1 LFE channel that would not be crossed over?

This is how it went.I am using the AUX input on the 990.I run analog cables from my computer to the 990.When I hit the sweep button on the computer it sends a signal sweep to the 990 AUX input and the signal is sent to the amps.My thinking is that a full range signal sweep is crossed over by the bass management section of the 990 and only signals below 100hz (my chosen xover point) are then sent to the sub output.It seems the roll off is by the driver at aboput 450hz and no lopass is processed by the 990.

I ended up sheving off the output above 100hz using my parametric eq for my subwoofer system.While this was a quick fix I'm sure there is a good reason for this.