Have just taken delivery of a subwoofer and get the above problem. Set sub to on in menu, crossover to 80hz, Fronts to large, rears to small. Works fine for DTS, Dolby Digital, Stereo, Direct, 5 Stereo etc. Use Pro Logic II 95% of the time so this is really annoying. I have even tried setting all the other speakers to -12db and the sub to +12bd just to see if the sub was set too low but still no output. I assume in prologic two that there should be a signal sent to the sub? Has anyone had this same problem and if so how did you solve it? Otherwise I assume the unit must be faulty? Any thoughts would be appreciated. Thanks in advance, Tony .