Sound reflecting panel

For quite a while concerned with an audible shift in the soundstage slightly 'left'. Even started wondering if my hearing was getting off. Long and short was that by accident, holding an LP out off the right side of my head, realized that perhaps it is the array of the room i.e. that right-hand-side leads to a very open and lengthy part of my house, the left side has a couch parallel to the speaker-listener path, then a much shorter distance (about 1/3) to a wall. Set up some plywood panels and indeed, correct soundstaging.

With that in mind, are there products that could fold out as temporary sound reflecting mechanisms? Think in terms of a (what do you call those folding panels folks used for changing clothes behind? Old sensuous film noir scenes.)

Now, if I've missed something critical, by all means open to suggestions/comments.