Lots of good thoughts above, and most likely several of the factors that have been mentioned are contributing.
But I would single out the short distance from the listening position to the windows as likely to be the most major contributor, despite the fact that closing the curtains/drapes does not help significantly. I would go so far as to say that I would be surprised if having a reflective surface like that so close behind the listening position did NOT cause the kinds of problems you are describing.
Basically what you are hearing is the direct sound from the speakers plus a lower amplitude version of the sound delayed by several milliseconds (as well as altered in frequency response, both by the reflective surface and by the fact that our ears respond differently to sounds arriving from the front and from the rear). To the degree that the reflected energy is strong enough to be significant, that results in comb filtering, with a lot of it being right in the mid-range based on the distances involved. My understanding is that that kind of effect would correlate subjectively with a general lack of clarity, or what you are describing as a veiled and muffled sound. There would also obviously be effects on imaging.
If moving your listening position forward, as was suggested, doesn't lead to a satisfactory resolution, I would look into the possibility of some sort of large sound absorbent panels that could be put in place in front of the windows during listening sessions, and put away at other times.
Regards,
-- Al
But I would single out the short distance from the listening position to the windows as likely to be the most major contributor, despite the fact that closing the curtains/drapes does not help significantly. I would go so far as to say that I would be surprised if having a reflective surface like that so close behind the listening position did NOT cause the kinds of problems you are describing.
Basically what you are hearing is the direct sound from the speakers plus a lower amplitude version of the sound delayed by several milliseconds (as well as altered in frequency response, both by the reflective surface and by the fact that our ears respond differently to sounds arriving from the front and from the rear). To the degree that the reflected energy is strong enough to be significant, that results in comb filtering, with a lot of it being right in the mid-range based on the distances involved. My understanding is that that kind of effect would correlate subjectively with a general lack of clarity, or what you are describing as a veiled and muffled sound. There would also obviously be effects on imaging.
If moving your listening position forward, as was suggested, doesn't lead to a satisfactory resolution, I would look into the possibility of some sort of large sound absorbent panels that could be put in place in front of the windows during listening sessions, and put away at other times.
Regards,
-- Al