Have you read the DSP speaker manual? You have to Type the speaker and config it to respond to the SL not SPDIF. Power OFF/ON + MSR 0.

Also make sure master DSP SL is in the correct master socket of the 818. This may be why they don't respond.

This setup is actually one of the most straight forward. You will be only a click or two away from lovely sounds.

Rgds,
Nick