Not sure which PS Audio, but trying different filters, along with the volume control is a thought.
For kicks, do you have a local guitar center? go pick up one of the inexpensive or a couple of the inexpensive crown pro amps. See what a crap-ton of power does for them. You likely won't be keeping the crowns, but GC has a liberal return policy. Just for kicks, see what some serious cheap, but powerful class D does with them. Probably hard to find an amp more different than your Leben (seriously) a quick and dirty way to find out if it's an amp/power issue.
If they still sound flat... think room, or frankly maybe they just aren't the speaker for you.
(I'm not claiming the crowns will sound good... but it should/will address if a radically different amp changes the sound)
For kicks, do you have a local guitar center? go pick up one of the inexpensive or a couple of the inexpensive crown pro amps. See what a crap-ton of power does for them. You likely won't be keeping the crowns, but GC has a liberal return policy. Just for kicks, see what some serious cheap, but powerful class D does with them. Probably hard to find an amp more different than your Leben (seriously) a quick and dirty way to find out if it's an amp/power issue.
If they still sound flat... think room, or frankly maybe they just aren't the speaker for you.
(I'm not claiming the crowns will sound good... but it should/will address if a radically different amp changes the sound)