I wonder what would happen to these resonances with (subs and) a typical high pass at 80Hz.It's been suggested that shoving the port round the back minimises interference from the direct sounds from the front, but it appears not to be the case if these upper midrange resonances are screwing with an otherwise well behaved driver. Short of blocking the port either completely or with dense foam, thereby creating a 'controlled leak,' any ideas as to how these comparatively nasty midrange resonances can be better tamed while keepngat least some of the benefit?
Has it been measured?
Same for distortion measurements.