Temporary wall ideas. Trying to create an enclosed room in rental house.

I am wanting to create 2 walls to enclose my theater room without constructing things to the actual home. This needs to be removable without noticable damage to the existing space. I don't see myself moving any time soon, but you never know. I wondered about heavy curtains with a lattice structure to support them.

The rear of my theater space is the staging area for all projects or sale item storage. This back wall changes all the time. This affects the sound in the theater greatly. Sometimes it's much better (diffusion is my thought). Most times it's worse. Currently the back wall is empty and things sound thin and peaky. My thoughts are to create a wall of curtains directly behind the rear surround speakers. This would allow me to have a uniform surface that doesn't change monthly. We could still use the space behind the curtain for staging sale items and whatnot. I would then make a second curtain wall to enclose the theater area. It's open to the entire basement. That's a lot to pressurize. I realize the curtain won't stop bass from traveling, I'm just trying to make a makeshift room hoping for better acoustics. Or at least more consistent acoustics.

I can provide pictures, but I was hoping to get general ideas with pro's and con's of the different materials mentioned. I'm not looking for things that will only work for my situation. I can't imagine I am the only person who would like to create a room without constructing walls. Then again, maybe I am. Any and all recommendations appreciated.

Thanks everyone for the ideas.

Update. I hung curtains with a heavy lined back. Goodwill special. I will make some diffusion/absorption panels to hang or floor stand. The curtains were enough to fool Audssey. Things sound much better now. Looks ugly as heck but I know it will work.

I made these diffusion/absorption panels today. I will cover them with some fabric at some point. My work around is functioning. I know this all looks terrible. Just testing before I build the real thing with actual money.

That's the plan. They work well (for the cost). If I keep with the ultra cheap idea, I think landscaping fabric would work. 48 of those 1 foot square panels were about $80.00. I had some rockwool left over from another project. I'll need more of that. Each DIY box diffusion/absorption pannel costs $20-$25. to build. If we do some more vehicle radiators or air conditioning condensers at work, I will have more boxes to use. I hate to wish bad luck for other people's cars, but I need more boxes.