There has been a fair amount of discussion of brackets used for mounting speakers, for my 3100's and 33's I used www.mypowerdrive.com , powerdrive out of the UK the model WME75-B, a bracket that can support upto 18kg, cost £42.30.
They have a series of brackets for most speakers, excellent products and good service.

Home Theater: LG 4K C7, HD621, G61RSL, Oppo 203, MS600, DSP3100 L & R, 2x3100's centers and 4xDSP3100's surrounds. 2x REL S3 SHO and 2x REL habitat1 subwoofers.
Music & TV: Sony 4k XBR 65", Oppo 203, HD621, G68D, C15, 588, M10, M20's, M33's, 4xDSP33's
MD600, 2xTwinStores.. 2xMS600, F80, Prime headphone and PSU.