Rear wall designs and there acoustical differences

[leon.payne]

I have been thinking about the rear wall in control rooms and i would be grateful if someone could shed some light on the acoustical differences of two different designs of rear wall.
Basically, if you a room with insulation on the side walls and on the rear. If both designs have the same volume of insulation, is there a difference or benefit to angling the insulation in the rear wall as apposed to having it flat?

i have included an illustration.

[Soundman2020]

The advantage is on the corners: You get a "free" boost in treatment efficiency on the corners: theoretically, 12 dB in wall/wall, wall/floor, and wall/ceiling corners, and 18dB in tri-corners (where three surfaces meet. You only get a 6dB boost from a flat wall.

That's theoretical for normally incident waves, of course, but its nice to take any free boost you can get!

So bass trapping makes much more sense in corners than it does up against a wall. That's why you normally put superchunks in your vertical corners, since they are very effective there, and just put flat insulation up against the rest of the rear wall (complete or partial) to deal with mids and highs.

- Stuart -

[leon.payne]

thanks Stuart