Complex sentence: Magic Band members have also said that the slower performances were due in part to Van Vliet's inability to fit his lyrics with the faster instrumental backing of the earlier albums, a problem that was exacerbated in that he almost never rehearsed with the group.
Split into simpler sentences: Magic Band members have also said that the slower performances were due in part to Van Vliet's inability to fit his lyrics with the faster instrumental backing of the earlier albums. This problem that was exacerbated in that he almost never rehearsed with the group.