Creating filters manually, can it render decent results?

[Joffieb]

Hi all,

I have a 2.1 system and only want to EQ my sub with a miniDSP but my mains overlap the sub and are causing nulls.

I’d like to try and work out filters to reduce the nulls by lowering the frequencies of the subs at the nulls using the miniDSP.

If the resultant measurements lift the nulls and look good in REW, have I done a good job? What smoothing should I be judging in? Also, any pointers on creating filters would oblige.

Thanks