NOTES from my first audition of the Oppo PM-1, excerpted from the Martin Logan Mikros 90 thread:
I initially strapped on the Oppos with negative bias and concordant expectation based on some of the reviews I had read beforehand, but by the end of the [long] evening and about 20 discs later, I had a difficult time taking them off and putting them away.
I listened to the PM-1 almost exclusively with the velour pads. A warmer, fuller [and somewhat meeker] sound with the velour- versus the lambskin pads, IMHE.
Preliminary a/b versus Mikros 90 [Yes. I realize that the MLs are closed portables.]
The Mikros 90 certainly held their own, but the decisive point came when I started playing older '70s recordings. The MLs were less forgiving than the Oppos [and/or not as well matched with the Lehmann BCL]. However, with the Oppos "forgiving" was not synonymous with syrupy/euphonic, bland or homogeneous. The PM-1 presented these recordings with remarkable deftness, clarity, resolution, and a disarming ease. This phenonenon reminded me of my first foray with the Denon AH-D2000: older "classic" rock and pop recordings, rather than sounding harsh or thin, sounded musically rich and well-recorded. [The PM-1 resolve appreciably better than do the D2K, BTW].
PM-1 bass: rounded, warm and liquidy, with a judicious measure of midbass weight and lick, excellent micro-dynamic texture and good reach [though ultimately not as dense, percussive and cavernous as the Mikros 90].
PM-1 midrange: pure, refined, detailed--nuanced in its resolution--and [again] liquidy.
[The PM-1 emphasis is on refinement, while the Mikros 90 emphasis is on candor--a more "stark" (but with a positive spin) sort of clarity--with a bolder front and more overall midrange musculature/"carry". I realize that this is an odd observation, given the fact that the PM-1 are themselves "midrange-forward" in character. But this may be due to the ML's well-integrated treble edge which lends to the Mikros 90's more even-handed--and excellent in its own right--midrange advance.]
PM-1 treble: delicate, refined, nuanced and smooth--for me "smooth" does not connote a muffled or blunted treble; "effortless" or "easy" might be a more apt descriptor here.
[The Mikros 90 have a more rawly energetic/vivacious treble, which seems to better support/carry musical passages rhythmically, at least for me].
Some additional [treble] commentary:
The Mikros 90 [Stock Pair #3/opened May 2014, w/HeadphoneLounge UPOCC copper litz re-cable] better suit my listening tastes with respect to their high frequency presentation and dynamic/ambient reach, but I was able nonetheless to make the adjustment to the PM-1's "golden mean" or "optimal modicum" way of keeping practically everything intricately balanced. I would not classify the Oppos as "rolled off" in the treble per se, as-in "lacking extension" or as-in "lacking detail", but I would describe them as being reticent/reserved in the upper reaches, yet all-the-while remaining highly resolving and remarkably refined.
Given my longstanding predilection for an "airy" and treble-leaning [many would call it a "bright"] sound, this is precisely where I feared--based on those negative facets of the reviews that stayed in my mind--the PM-1 would grossly disappoint me. But I am glad [and, frankly, surprised] to find myself truly enjoying the Oppo's treble response, even though it is neither what I expected nor even what I thought I would otherwise have preferred: a welcome serendipity!
PRaT: The Mikros 90 get the clear edge in this department, the MLs offering a more robust, sinewy and straightforward dynamic attack. I really enjoy these unassuming little closed, portable gems!
At any rate, I think I could live with the Oppos for a while. They are a worthy full-sized, open complement to the Mikros 90, and the first set of planars that have really managed to turn my head in quite some time.
LOL