Currently all pre-made wall mounts are sold out. So I tried to make my own.

40mm clearance from back of speaker to wall (sonos recommends minimum 25mm)

Embedded steel bracket (90x90x40x3 mm).  As the speakers are placed above the heads of delicate humans, I did not trust plastic alone.

The speakers rest on the wall mount on their rubber feet. Two M5 30mm fasteners attach the speaker to the mount. There is a small (3mm) gap between the bottom of the speakers and the mount.

Printed in PETG, 10% infill, 5 parameters. I used “helper disks” on the ends and corners but still had a problem with warping,  better to use brim all around.

Please note that each steel bracket weighs about 150 grams. I printed two wall mounts at once @.30 layer height and “quality” setting on my Prusa Mk3. (.6 nozzle), and that was OK. But a bedslinger has its limits, and it is safer to not use maximum speeds/accelerations with heavy objects on the print plate.