Tuning crossover, trying to dial in plucked strings

Hi All, I've printed a waveguide using Augerpro's model: Waveguides | somasonus

Now I have constructed a box with a Dayton RS225-4 and an RST28a and after some measurement and tweaking it's sounding fairly good. I'm targeting a flat on-axis response with a goal of 6db drop from 100hz-20khz in-room at the listening position. A 1.5khz 4th order crossover in the MiniDSP 2x4HD with a few parametric cuts per driver has got me there and voices are sounding good.

At this point it sounds like I'm more than halfway to where I want to be, but at the moment I'm hearing a bit less 'attack' and 'clarity' than I'd like to hear. As an example, the plucked strings in Hotel California aren't quite as distinctly separated as I've heard on the best speakers and headphones I've heard it on.

Dear knowledgeable DIY Audio forum participants, where do I look next? Can the tonality seem about right (voices sound pretty good) and have a problem with this if I haven't got the phase just right? Or is it likely to be a problem that can be fixed with EQ?

I'll post whatever measurements might be helpful. Thanks for any advice!
 
I guess it's a matter of personal choice. This isn't far from what I see from the JBL LSR 308P MKII, and I think that sounds fairly good. I've tried equalizing to flat at the seat before and it seemed overly cold/bright, too bass shy.

An update on my design- I tried scanning a parametric EQ bump of a few decibels and a Q of about 1.5 to see if I could locate the range that's problmatic and it seems to be right at or above the crossover. It seems that my next step should be to put crossover summation under a microscope to see if that's going worse than I thought.
 
Try a higher crossover frequency. I recently used the RS225-8 (8 ohm version of the RS225-4) in an MTM build and liked the sound more when crossed at about 2 kHz instead of 1.5 kHz. My system is active but with an ART CX311 analog unit which is 4th order LR.