If you like the sound, you use what you like. But the 10" 425s, the 12" 417s, and the 15" 418s are designed for guitar/organ/pa and NOT bass the (the 15" 421s). Same same with the JBLs (15" D...K 130s & various 12' 120s versus the various (LF) 140s. Just sayin'. All that stuff is hi fi sound at...