My sony manual for my str-de985 receiver tells me that setting my Dynamic Range Compression to their STD setting is "to reproduce the sound track with the dynamic range intended by the recording engineer". ive always left the compression off because i figured it was a feature only for late night listening. When is says it is meant to reproduce the sound track with the correct dynamic range, does that mean it is keeping all frequencies 20kHz-20Hz? I know there are subharmonic frequencies from adding to the sound track? can someone explain to me why I would want to leave the compression set to STD and not off?