Hi DanDan,
As I recall, that is from Jeff Szymanski's "in-house" testing in the Auralex testing lab (likely 2006). I don't think Auralex ever took the product to Riverbank. One of the issues with testing the "Coupler" in a Riverbank situation beyond sub 125 Hz room variance is how the Coupler redirects off-axis reflections toward perpendicular impact with absorber. Acoustical testing labs test only normal incident reflections. So it's somewhere between an absorber & a diffusor.
In use, I've had most success at mid-wall axial pressure points compared to corner assemblies.
Attached is front & rear views of small control room where the Couplers made great difference in conjunction with passive soffit traps that wrap the side & rear walls.
