Personally, I'm working on getting rid of the enclosure entirely, except for the low fq. Not a new concept, but taking my own approach.
As for 'noise' cancellation, unless it's a reasonably steady source one would have to employ a means of inverting the incoming sound(s) at a matching db. Get Smart's Cone of Silence comes to my mind...
Even if it could be set up to be 'selective' as to what needs to be canceled, it would likely damp 'wanted' fq as well. Speech would make anyone within the field being effected sound very strange IMHO.
Set That up on your porch for Halloween. The kids would think they've arrived a Real haunted house... ;) "Trick or Treat", indeed.