You can't really stifle a sub without using a mattress or two. Rattling is the big problem, not muffling. With your layout, I think placing the sub behind the sectional might be the ideal location.

Only concern is that your room shape looks a bit square-ish. Do you happen to have the dimensions handy (L W H) ? Sometimes you get big peaks and dips in the frequency response of a square room and positioning the sub away from the corners can help. Sometimes.


M60ti, VP180, QS8, M2ti, EP500, PC-Plus 20-39
M5HP, M40ti, Sierra-1
LFR1100 active, ADA1500-4 and -8