Use the Inserts on the subs, not the sends... until u can really graps the main diference between Aux Sends and Inserts u probably better off using the insert on the sub... U need a Y cable (aka Insert cable) which starts as a Jack 1/4" TRS (tip, ring, sleeve... which is know 2 many as a stereo jack, but can also be a balanced mono) and ends in 2 Jack 1/4" TRS (Tip, sleeve - comonly know as a mono Jack), one will b 2 use on the in of the compressor and the other on the out....

Z