Thanks for the quick replies. I totally agree that the listening space is crucial, not off-base at all. I have had the system in different rooms and my listening room is currently treated with a good number of GIK panels and bass traps. The room can cause issues, but I don't it's affecting the main issue I'm hearing.
I usually don't toe in speakers at all, and the Buchardt recommends to keep them straight. Toe-in does make the sound brighter, but I don't feel it affects the main issue I'm trying to describe. To exaggerate, the transients feel like loud noises that make you instinctively close your eyes.
My ears are evidently particularly sensitive to this. I knew that I could only listen to headphones at very low volumes, but before getting into better gear, I had never had issues with speaker systems. Would be interesting to hear if anybody else has had something similar.
Thanks for the Luxman recommendation. That's a brand that I associate with the kind of sound I'm looking for, but haven't had the chance to test and it's unfortunately not in my budget.