" At times my [6.5" two-way] speakers, while having superb resolving ability, can occasionally sound edgy, particularly noticable with voices at higher volumes. "
Here is what might be happening:
In the octave or so north of the 2.2 kHz crossover the tweeter has a very wide radiation pattern, so there is an abundance of off-axis energy in this region. This happens to be the region where the ear is most sensitive. Some designers intentionally put a dip at the bottom end of the tweeter’s response which restores timbral balance at the expense of some clarity, as now the upper harmonics in that region are under-represented in the first-arrival sound.
Your comment that your speakers have "superb resolving ability" makes me think their on-axis response is pretty close to flat, which implies the presence of excess off-axis energy at the bottom end of the tweeter’s range.
You might try this: Turn them up a bit louder than normal and listen through an open doorway from outside the room, with no line-of-sight to the speakers. All you will hear will be reverberant sound, whose spectral balance will be dominated by the off-axis energy. If you hear that edgy signature from outside the room, it may well be due to an excess of off-axis energy at the bottom end of the tweeter’s range.
If this is indeed the case then you might try listening nearfield, to minimize the loudness of the reverberant field relative to the direct sound.
Duke
