Something is not right in what you're stating. The 58 to 70Hz suckout is fairly narrow and not that deep. I don't see how it would take the life out of the bass. Your room dimension are not good. Rather than swap equipment I would recommend you hire an acoustic engineer to measure your room and see what he recommends.
Speakers to alleviate room anomolies
I have a suckout of 8db from 58 -70 hertz which is taking the life out of the music. I currently have Von Schweikert VR7SE an added a velodyne dd18 which took away the problem. It gave the bass energy in my room of 30 x20x10. It seems I do not need the big cabinet speakers[VR7SE] if the woofers aren't throughing enough. Speakers with active woofers like the evolution acoustics mm2 have been recommended. Any other ideas of speakers in conjunction with the velodyne dd18 to make my room sing again.