Is carpet on wall behind speakers counter productive?

Not a problem. I have set up systems with a carpeted front walls. Saves you from having to find reflections and dampen them. The carpet is not as good as 4 inch acoustic foam but if you are not using dipoles you probably do not need it. Leave the carpet up!

i prefer heavy curtains... looks a little nicer imho

Just because something is soft, and therefore might seem absorptive to sound, does not mean it is.

There is no way, without doing some pretty extensive tests, to see at what frequencies the specific carpet you have, will absorb.

And maybe, your particular room does not need absorption at those frequencies.

And finally, deflection may be better (and usually is) behind the speakers, where absorption is usually better on side walls and ceiling.

You are just rolling the dice, with the odds against you, that some random carpet will help in your particular room.

simonmoon, the carpet is already inplace and has been for years. It was aimed at splash-over from projection, a problem I no longer have. I think I’ll follow mijostyn’s suggestion and leave it up. Above 2’ most of the wall between the speakers is covered by a Stewart 100" screen.

I’ll concentrate instead on relocating the equipment rack from between the speakers to an adjacent wall. As has been my usual practice, only the amp will sit on the floor between the speakers.