Hi All, I have a Pioneer VSX1014 reciever and have a little problem. I have recently purchased a kef psw3000 sub to go with my KEF Q4's. The Q4's play down to around 45hz and I want to sub to take over from around 50hz. I have set the crossover to 50hz on the amp and I need to set the sub setting to PLUS and the front speakers to large, this should output all frequencies to the front speakers and sent <50hz to the sub. However when i change to the PLUS setting, the volume output dips by probably 6db's, requiring the amp to be on 0db and occasionally +2 or +3 db to get any decent volume from it, If I switch the sub setting to off then the volume jumps back up. Is this usual on AV amps or am I doing something wrong?