I am also wondering the importance of having an "air gap" and if filling an air gap with more 703 is preferred over leaving the space/air.
What would be more beneficial:
1) A 4" 703 panel in a corner - this yields an approx 12inch air gap to the corner point
Or
2) A 4" 703 panel with an additional 2 foot wide (so it fits) 4" 703 panel behind it - this would narrow the air gap to 8 inches to the corner point
I ask because doing this will cost money. Logic tells me thicker amount of 703 equals better absorption but I see lots of posts about the benefits of an air gap.
For those interested this is what option two would look like sitting in the corner:
NEST™ Corner Mount System - Ultra Sub Bass Traps Ready Acoustics, LLC - Afforadble, Durable, and Stylish Acoustic Products - Bass Traps - DIY! Solutions - Mounts - Insulation [RANCM] - $299.99 : Ready Acoustics!, Hear - Sound - Better
No I am not buying that product but am considering DIYing something similar if it will increase and extend my low end absorption.