DB, your curve looks quite good except for that depression around 40-50Hz and indicates that your room dimensions may be favorable. You say M60s are set "large filtered at 80Hz", but large is a full-range unfiltered setting, so could you clarify that point? For example, if the M60s are running full-range it's possible that at certain distances from the 20-39 and frequencies they can possibly conflict and cause a partial null in the overall bass response, such as appears around 40-50Hz.

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Enjoy the music, not the equipment.