I have built a new QRD diffuser, and some have asked how I like it, and where
it came from.
Here it is installed:

Like everything in my room (except amp and CDP) I built it DIY.
It was very easy and matches with my V-1 better than I ever imagined.
It was designed on the QRD Dude, a user friendly program. You simply punch in the well width you want, the length you want and the depth you want. It explains how it will perform and what you can do to improve it.
My diffuser was made in mind with material I had on hand, and the space I had to work with. There are probably better designs, but this was an experiment and I wanted to keep the costs low in case of failure.......

I work with styrofoam so thats what I used, white popcorn type, 1-1/2" wide. I have access to a hot wire cutter but you can easily cut it on a table saw. Its glued on to a 1/8" backer board, the glue being spray foam in a can. Spray foam is also what is used to bond the styrofoam pieces to each other, very simple....so simple that I built the QRD in my living room. It took about 9hrs total over 3 days.
After the pieces were adhered to the board and set overnight I used a thin set mortar
mixed to a paste consistency. Then I used a 2" paintbrush and coated the whole QRD
with a thin coat. The next day I painted and then glued.....again with sprayfoam...a pre finished black shelf from Home Depot to the top and bottom.
The whole QRD is about 7'-6" long and 4' wide, weighs less than about 40 lbs. My wife and I hung it easily.
Some construction pics:





The poly diffuser that I have had in my room for a while now did a great job. This one just seems to get me more overall depth in the soundstage,and a bit more width. The biggest improvement seems to be in that voices and instruments are coming from a more precise point....if that makes sense. It has also given height to the presentation but I think that is because my poly was only 4' high and on the floor.
This is very easy to make, like I said I built it in my living room, with very few tools.
If you have the capabilities go for it, if you dont like it you shouldnt be out more than a hundred bucks.
Perry