I have a lot of respect for Crown. They really do seem to care a great deal about quality and not just brute force. Now I don't mean to sound like a jerk but I've never heard an amp that sounds better in bridge mode. Tried a handful of various types and the bass gets loose. They just seem to loose a great deal of woofer damping. Try your amps in stereo mode and I bet the bass gets tighter and more defined. You could even "vertically" amp your system. Use one channel from each 400 for your mains and the other channel for the lower powered Hafler speakers. This frees up the power supply somewhat.
"Not the most accurate system by far, but just plain enjoyable".....that's exactly what this hobby is about. You can spend a lot of time and money chasing the dragon. I gave that up long ago. I currently have the least expensive stereo that I've owned in some time yet is my most enjoyable.
I am always open to better ways of wiring up my system and since everything is self contained in a rack on wheels, making changes is simple as wheeling out the rackand turning it around. No having to be a contortionist. 1/4" jacks make easy work of this. just slide them in and out. No wiggling of pesky, tight rca jacks.
As far as loose bass is concerned, that duty is handled by 3 velodyne servo subs. (one left, one right, and one stereo. with nine 4" drivers in each cab, bass is very controlled.
I want to thank all of you for not bose bashing my system.
901's sound like shit when mated with a common reciever. I'll admit that. Put well over 500 watts into these things and it's a whole new ball game. It mesmerizes everyone who has had the chance to audition it. Even after having this configuration for years, I still am left with goosebumps. No crossovers to worry about, the amps are bullet proof. You can play this system just below clipping for days without fear of blowing anything; except something in my breaker box.
Clarity and detail is not what this system was designed for. At levels where many systems, begin to falter, this one is just coming in to itself.
I invite everyone in this forum to come and hear it for yourself. Beer and Tequila is always plentiful.