A:Answer Yes they can be added to your system. I have the same 900 setup. The surround speakers added depth and filled in the gaps to create a 5.1 surround experience. Be aware, though, the rear surround speakers only seem to work when streaming content or music that is in the 5.1 format. But, I highly recommend the surround speakers for your system. I was thrilled with the 900 bar and bass module, and blown away by the added depth of sound from the surround speakers. Buy them!