I found that the improvement from even simple acoustic treatments was surprisingly large. In my case the problem was a highly reflective rear wall -- even simple treatments (eg. holding a pillow behind my head ) took me from no imaging to extremly good imaging.

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