I have the Magnepan 1.6 speakers. Haven't seen the .6 but I have a subwoofer installed in my system to supplement the maggies. I have them powered with a Outlaw 7500 which is also 300 watts. I usually listen to music and feel that the bass is more than sufficient for that use without the sub but...the sub allows the maggies to use more power from the amp in their best range to give me more headroom. I would start with one sub or maybe 2 smaller subs depending on your room size. That should be more than enough especially at lower volumes. I cross my sub over at 80 hz which works well for my room which is very small.