Hello Ludwig,
Yes I have mounted a set of DSP3300's for my side channels using the mounts that are called out in the Meridian DSP3300 brouchure. I am using the Konig&Meyer 24481 mounts there are another also which are the 24471's. The 24481's are very heavy duty and of good quality. I did have to sightly modify them so I could mount the mounts to studs in my wall the DSP3300's are very heavy and the mounting has to be very secure.You can find them if you go to K&M's web site. Hope that was of help.
Highrez

861v8, 808v6, 800v3 w/LPSU, HD621, MD600, DSP8000.2USE, DSP7200.2HCUSE, DSP7000 (rear)w/2 Revivers, DSP3300 (sides elevated), Seaton Submersive HP Subwoofer, Sim2 3000e, Oppo BDP-103, Stewart Film Screen JK Gray Hawk Grand Cinema R/S 115"Diag w/masking.