If your speakers are set up properly and assuming you have a somewhat normal room there is absolutely no need for any room treatment.
Normal furnishings drapes, etc, do a remarkable job of letting the sound decay in a natural way.
If the speakers are not set up to act "as one" no amount of room treatment will ever get you where you want to be.
Normal furnishings drapes, etc, do a remarkable job of letting the sound decay in a natural way.
If the speakers are not set up to act "as one" no amount of room treatment will ever get you where you want to be.