If you have an AV Stumpfl Projection Screen and want to mount your old Creative Labs surround system satellite speakers on top of the frame, this might help. The holder was measured from the original holders supplied with the Creative Labs/Cambridge Sound Systems DTT 3500 and fits rather snugly. The bottom bracket will fit onto the aluminium railings of the projection screen and can optionally be secured with a length of velcro band (the kind that's usually used to tie cables together. In Germany, it's available through Reichelt).
This thing was made with Tinkercad. Edit it online https://www.tinkercad.com/things/iiHZeLhMhRt
Cura, standard settings (0.4mm, PLA, Normal). I used a brim to prevent warping.