Cancelling out room Eigentones with a sub & DSP-LF

I have an annoying boomy resonance in my listening room at about 68Hz. I don't want to insert any filters into the signal path to my amp (Q909).

My speakers are Magneplanar MG1.6 and go low enough but can't be relocated to a position which doesn't excite the eigentonesso much.

So I was pondering on placing an unused sub near my listening position driven with a Dayton Audio DSP-LF and spare amp. In this case, adjusting the response to cancel out the boom rather than boosting the low frequencies.

Doable?