To side chain with logics compressor on 5.5 on pc, i bounce down the kick drum(if its an audio instrument), put the bounced kick on say audio track 1 then use the compressor as an insert on the bass track (or audio instrument, dont send it to a bus, youll just be defeating the object) then click the side chain box on the compressor and select the audio track the kick drum is on (audio track 1 in this case) err yeah...hope thats makes sense, its late and ive had a few what was the question again?????