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


I'm going to make some sound absorbing panels to place on the wall behind my listening chair. Owens Corning 703 and Roxul Safe 'n' Sound rigid boards are two choices to make them with. Anyone have experience with both, or even one?
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Excellent point about the thickness of 703 being so important at that frequency, but low frequencies are more likely to gather in the corners and the panels behind you on back wall will most likely only affect mids and highs so I would focus on absorption properties at those frequencies for you back wall panels. Corner traps behind you can use air gaps to absorb even deeper in the low frequencies. Corner traps in all 4 corners are the best way to deal with LF issues. The stuff behind your head can help with reflections, flutter echo, etc.in mids & highs. Cheers,
Spencer

All good points, guys. My desire to get some absorption of lower frequencies at the listening position originates from having read that bass modes/nodes build up at not just room corners (though that is where they are most prominent), nor not just also along all the rooms wall/floor/ceiling intersections, but also along the wall itself---sealed rooms sound "bassiest" against their walls.

I know it takes a whole lotta material to absorb very low frequencies (below 100Hz), so perhaps going beyond the 2-3" of typical absorptive wall panels would bring marginal improvement in that regard. I have room to place a 9" ASC Tube Trap at either side of my chair, so I could do that and set the wall panels atop them. The rooms two front corners (behind the speakers) will have 11" Traps stacked on the big boys---the 16 inchers, the rooms back corners stacked 9" Traps.

Thanks again ya'll---Eric.

Yes, that is true.  There can be a benefit to putting bass traps in the middle of the walls.  However, you will only be able to attack some of the axial room nodes (not all).  It's still a benefit, though.  The link here does a room node calculation for my current HT room:

http://amroc.andymel.eu/?l=17.5&w=11.25&h=9&ft=true&r60=0.6

If you move your mouse pointer over each of the axial room nodes (the tallest lines on the frequency chart), you'll see in the "Room 3d" graphic that some nodes will build up on the front/back walls, some will build up on the side walls and some will build up on the ceiling/floor.

Interest article I found here:

http://ethanwiner.com/density.html

Where Ethan Winer found that putting Twelve 3" 703-FRK panels in a room absorbed more bass frequencies than Six 6" 703-FRK panels.  These are frequencies down in the 40-80Hfz area.  Makes me think of using the 703 FRK instead, because my room is becoming a little too dead with the Rockboard 80 panels even.

The amroc program is exactly where I learned of all the modes/nodes in a room! What a great aid in understanding what's going on in any size room, and where acoustic treatment will give the most results. I hadn't seen Ethan Winers article, so thanks auxinput. I'm gonna read it right now.
Ethan has a Manufacturer's forum section on audioasylum that is full of great info relating to room acoustics and treatments. Much of the content is many years old but still among the most helpful I've seen. 
Lately, I've seen his name brought up in some controversy on other topics which I don't recall, but regardless, he is a top educator on room acoustics and he donated much time and energy in helping other with similar situations. Cheers,
Spencer