Quick Fix: Klipsch Bookshelf Speakers and Chromecast with Google TV

Connect your Speakers with a SPDIF Optical cable to your Television's optical out (SPDIF) port
then go into your televisions settings to set it to output to Optical out (SPDIF)
to get chromecast remote to control sound volume you simply choose Soundbar > Klipsch and follow the instructions on your chromecast