You can run powered speakers out of the main left and right output and still run the ms 4 system and have a full sound with out any loss .
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Genos, PSR S970, Fender Tele Amercian Deluxe Cherry sunburst , Cubase Pro 8 ,Yamaha A3M Acoustric ,Taylor 814, Ibenez Artcore Custom Tascam DP 32 Yamaha DXR 10, QSC K-12, K 12 Sub K 8 Sinn 945
2 Fender Expo line units .