Martin Logan Classic 9 vs. Impression 11A - sound impressions and burn in question


Hello! I have recently had the chance to compare the two models mentioned in the same room / system and my findings are a bit unexpected, hence my post here in order to share them with you and maybe get some help with an explanation of what I've heard. This could have a great importance in the light of a possible purchase decision so please chime in with everything you've got! These being said:

- the 9 were fully burned in, the 11A had maybe 10 hours or so on them

- the 11A were definitely more detailed throughout the frequency range, clearly more relaxed / effortless, amazingly with even sharper and better defined transients, better bass extension and perhaps slightly better highs extension too; they also sounded bigger and everything was better separated, whereas through the Classic 9 things were more... gathered together, let's say (I hesitate to call this "congestion" because this is true only by comparison to the better model in the series, by themselves the Classic 9 have great instrument separation and great soundstage); the bass was also more even and better controlled. The 11A I've heard is clearly the better model from a technical standpoint, no doubt about it, but it is also comparatively a bit drier and perhaps over-controlled or overdamped in the bass, thinner in the midrange, more cerebral and I daresay somewhat less involving

- surprisingly, the Classic 9 also had some advantages: the sound was more tactile both in the bass (a fatter, punchier and more cavernous low-to-midbass injecting better drive into the music, better PRAT) and the upper midrange (some small percussion instruments, I don't know their English name, were more, well, percussive), better emulating that pleasant tactility that is an advantage of the speakers with dynamic drivers; also, they were warmer, more colorful, bloomier (for better or worse), with a hotter (usually for the better, sometimes a bit overdone though) mid-midrange (around 1 kHz I guess) and fuller lower midrange, resulting in a better reproduction of the body of the stringed instruments, the chestiness of the vocalists etc.; probably this extra body combined with the slight "congestion" (see above) made for a more cohesive presentation with better musical flow; hard to describe, the bass, while rounder and more ambiguous, seemed also in a way a bit more natural

Interestingly, Noel Keywood has reviewed both models in  Hi-Fi-World  and in the 11A's review he states that these are brighter than the Classic 9. The measurement graphs at the end of the review shows a significant dip in the 11A's lower mids that is missing in the Classic 9's graph, which overall looks closer to the Harman curve.

So, my question is which of the drawbacks I've noticed in the 11A can be attributed to:
a) lack of burn in (a bit overdamped in the bass, clearly thinner in the lower midrange, less tactility...?)
b) the DSP and A-D / D-A conversion (less natural bass, less involving?)
c) sealed drivers vs the bass reflex design of the Classic 9 (less cavernous, fat, weighty bass?)
d) a different, intentional, voicing of the two models (I thought at least the panels should have a quasi-identical voicing?!)

What changes could I expect with the full burning in of the Impression 11A?

Thank you all!
donquichotte
When you go up the Martin Logan line a few things happen. One, the crossover point from panel to dynamic drivers is lowered. They increase panel size so now the electrostatic panel can produce more mid bass without substantial distortion. They also ditch a passive crossover network and go active. The congestion you hear in the lower models is the passive crossover network affecting the sound of the electrostatic panel. The larger ML's have more panel size so you get lower distortion and a bigger more detailed sound. Not a burn in issue with 11'a's. They will sound thinner and brighter because the electrostatic panel is now covering more of the audio spectrum.  Crossover point for ESL 9 is 380 hz to woofers. 11a is 300. 400 square inches of panel for ESL9 VS 500 for 11A. The Esl 9's will sound fuller because of higher crossover point and passive network coloring the panel.  Esl 9 still sounds fantastic.  11a's have more detail, less distortion but it's up to you which sound you prefer. 
@jeffvegas: What you're saying makes perfect sense, although it's not what I wanted to hear. Have you heard these two models?
@emailists: PM sent.
Thank you both. I know there are other Impression 11A users around, I'd appreciate more feedback especially regarding that lack of punch / tactility in the bass and mids and the dryness of the bass.