Owens Corning 703 vs. Roxul Safe 'n' Sound?

Thanks everyone. Home depot sells and stocks the Roxul 3" Safe 'n' Sound in a 12-pack of 15-1/4" x 48" panels for $46.27. Such a deal! Lowes sells them in the 24" width, but with a three package minimum. WAY more than I need.

Here's another question: Should I try absorption on the rest of the back wall (behind the listening position), not just directly behind my head?

At $47 for a 12-pack, you can just stack them up in the back of the room to see how it will affect the sound. They 15-1/4" are cut to fit between house frames. If you don’t mind putting up 3 panels instead of 1 or 2, it can be a cheap way to go. The Roxul are only 2.5 lb density, but they might be stiff enough to lay up against the walls. If you do this, be very careful. It is mineral wool fiberglass and always use a filter mouth mask and gloves when handling them.  There's a point where there will be too much absorption in the room.  You'll just have to experiment until you find that threshold.

The panels from ATS Acoustics are mounted in a light wood frame and wrapped with fabric. At $55-76 per panel, it’s really cheap for the build labor. Unless you are fine building them yourself.

Nah, I’ll make one frame sized to fit three pieces of the Roxul in, 45-3/4" x 48" interior. There is 56" between the two doors that flank the listening position, on the wall opposite the speakers. I might put a Roxul strip on each of those doors too, if they prove to be reflecting too much sound over to the lp. The space between the doors and the side walls is far enough away from the lp to be of no concern to me. That’s all the absorption I want---just to kill the first reflection from the speakers pointed at the lp wall.

The room sounds fine overall, no glaring problems as far as I can tell. I have ASC Tube Traps and a DSPeaker Anti-Mode for low-frequency eigenmodes, and MG CornerTunes and EchoTunes for any slap and flutter echo emanating from up near the ceiling. The wall behind the speakers will remain reflective---fine (in fact, preferred) for dipole speakers, as will the sidewalls---no need, due to dipole cancellation. First, I’m painting the room, this weekend, hopefully. I chose Sherwin Williams "Mink", a combination of gray and brown that is absolutely beautiful!