@flasd wrote: "Either too much treble..."
"Too much treble" can be a symptom of "not enough bass".
@flasd: "Room dimensions: 11.5’ W x 12’ L... Listening Distance from Speakers 8.5’ - 9’..."
This implies your Maggies are pretty close to the wall behind them. In such cases, it is the out-of-phase backwave which is getting the benefit of strong boundary reinforcement from the nearby wall, resulting in greater cancellation of the in-phase front wave and therefore weaker bass. I know it's counter-intuitive to think that pulling speakers away from the wall will result in more bass, but that is what happens with dipoles. On the other hand the closer your listening position is to the wall, the more bass you will hear, in general.
You might try this if you have the freedom to do so: Since your room is almost square, set up your system on a diagonal, with your chair in or near a corner, with the midpoint between your speakers about 2/5 of the way out from the opposite corner along that diagonal. I haven't tried this but it might be a way to pretty much maximize the low end and thereby fix the tonal balance.
Duke
dipole speaker dealer since 1999