Try the speakers out first. If you find the treble is too exaggerated, then you can consider some absorbent curtains over the window. If you were using bipolar or omnipolar speakers, which use rear-facing drivers, then the windows might significantly affect the tonal balance.
Normal furnishings of room interiors -- fabric-covered couches, area rugs, bookcases, etc. are usually sufficient to create a mix of absorbent and reflective surfaces, which is what you should be aiming for. Axiom Loudspeakers are designed to optimally perform in normally furnished domestic rooms, and if you've visited Axiom, the listening room is furnished that way.
The need for room "treatments" is greatly exaggerated. Problems with deep bass boominess can usually be solved by re-positioning the speakers or listening chairs/couches within the room.
Axiom Resident Expert