All above plus you may want to try some of the Synergistic HFT. While my room is larger, I've found using these behind listening position on side walls helps to further scale up size of room. This has been added to room treated mostly with diffusion, preferable to absorption for me.
How to make small room sound bigger
Is It possible to make a relatively small room sound larger ? I have a 14 x 11ft with 8 ft ceiling. The room is completely empty, with vinyl floors with cement floor under. Looking into vicoustic sound treatments.
What would be the best approach with absorption vs diffusion and placement to attain a bigger sound space if at all possible ?
I wrote to vicoustics, but did not hear back.
speakers : SF Elipsa, Diapason adamantes, Focal utopia micro
amps: mastersound 845, mcintosh mc452, NAD M10