You have a digital optical 'out' (Toslink), so would be the ideal solution to use that. That way anything output on the TV would send audio to the speakers.
The alternative is use HDMI passthroughs, with HDMI from the playback device to speakers, then from speakers to the TV. The problem there though, is that only that one device will have sound. If you change input devices, you'd have to re-arrange cables etc.
What speakers do you plan on using?