Snazzy! I like it.
You have correctly picked up in your testing that the cab is unforgiving of a bad signal chain. If your bass, amp, EQ, fingers, strings, effects are not all good, then it will simply produce that bad sound. However it sounds great once you make sure everything is sorted.
I can see the dilemma of bass cab manufacturers. If you make it voiced, then it will almost certainly conflict with the voice built in to some instruments. However, leaving it flat/unvoiced means many players who are not attentive to technique, etc, may not necessarily sound very good through it.