To me this looks like a decent live sound subwoofer aimed at deep bass output. It looks like it does the job very competently. With respect to resonance, that would take the form of stored energy, and there is nothing on the group delay graph nor on any other acoustic measurement that would be cause for concern. The naked response is not flat, but who cares since it can and definitely will be EQ'd where ever it will be used. This is not a wide-band subwoofer, but again, who cares, it is tuned for deep bass, so low-pass it at 80 Hz. The deep bass distortion behavior is very good, even out to 120 dB. Looks to me like it may do well with music after equalization.