yamaha htr-6250

Hi, Got Mackie's MR5, and Yamaha HTR-6250. I can not figure how to connected than - other than plug speakers into a front 1\4 jack. Problems are: A) Have to plug via a split-Y cable, which is an issue 'cause B) It hissing - and it's REALLY annoying. Using receiver to get HDMI video and audio...