according to scott, the 950 has a fixed lp of 120hz on the subwoofer channel in 6 channel bypass. this is as it should be so as to not lose any of the original information, and this is high enough to allow outboard crossover/slope processing.

setting the switch to off sends 80hz and below from 5 channels to sum with 120hz and below in the sub channel. (i call this obese bass)

remove the cable from the 950's sw output to your sub amp. take the rca plug out of the 950's sw input and insert it into an $80 mono mic preamp, then into your sub amp. the sub will then only see lfe info (directly from the sacd player) and the summed below 80hz signal will go nowhere.

this will also work for HT, as the player will send the decoded lfe through it's sw output also. of course, this is strictly for an all speakers set to 'large' setup.