I put up some velvet curtains on the front and side walls and they seem to have eliminated enough of the early reflections to increase focus, depth and imaging quite noticeably.
Good Materials for Curtains
Has anyone made heavy curtains specifically to add absorbance to a room, and (of course) to block the reflections of glass? If so, what materials did you use. This is such a simple and common acoustical technique, yet I can find little written about what types of fabric (etc) are best. Thanks for your experienced suggestions.