I built my own using QRDude.
Foam cut with hot wire and then a thin set applied with
a small kinife on the foam, then paint to match.
It really was easier than it looks.
It was fun to design and build as well......but, I'm a DIY nut.
I must of had these for 8 or 9 years now.
https://www.subwoofer-builder.com/qrdude.htm
This was an earlier attempt.....just a poly diffusor made simple with a 1/8" of
your choice of panel....
