Removing the grill cloth improved the speakers' tonality in the upper midrange, but the speaker does not look correct this way, and an even heavier hand on the treble control was required.
I have found that speakers that have subjectively abrupt changes in tonality can sound strange even on the speaker's optimal axis (this effect is usually correlated with measurements showing changes in frequency response over a wide area of the midrange spectrum, not just near the tweeter crossover point.
Harshness dissipated significantly and some warmth in the lower midrange reappeared.
Plenty of bass power with no boom or overhang, and open midrange, and treble that sounded just right--not too dull, not too bright.
The 20/20s without the Step One processor sound more open in the midrange and treble and more controlled and powerful on the bottom end than the previous version had sounded with the processor (which worked to increase perceived separation in the midrange frequencies and to offer flexibility in fine-tuning the bass response in a room.)
The treble sounded smooth and non-peaky to me, but even though it was bright, something seemed a bit off; maybe it was not quite balanced overall with the midrange somehow.
Returning to the reliable midrange sound, I began to notice that sometimes its accuracy changed with head height and position, and there even was a marginally cupped or very faintly boxy character sometimes in various parts and relationships among the lower-midrange/upper-midrange/lower-treble balances.
I won't lie and tell you I heard right away that the midrange sounded lumpier, as is clearly shown here, than in the cathedral-ceiling room.
Will you look at that midrange! It is not often that you see, or hear, the 200 Hz to 2 kHz decade done @ 2 dB, with even more marked flatness within it.
An important plus of the Phase Tech's neutral midrange performance is that the listener can readily EQ the speaker.
I believe the combination of a flat upper midrange with the slight rolloff at the high end (see Figure 2) is responsible for the speaker's excellent tonal characteristics.
An upper midrange depression (we are talking about something that is present in many so-called audiophile speakers) may sound pleasing in stereo, but it is a wart in the tonality of a surround sound system.