Can you connect Ropieee to a subwoofer?

Can Ropiee, running on a Raspberry PI, be connected to a 2.1 (stereo speakers + subwoofer) set? Specifically:

  • can it be connected to a soundbar (i.e. no amplification required) with built-in or external subwoofer?
  • can it be connected to passive speakers + a subwoofer, i.e. acting as an amplifier?
  • what connections would I need? E.g. soundbars tend to have a 3.5mm analogue jack and a digital toslink. Would the subwoofer work with both? Only with TOS link?
  • what hardware (hifiberry or other hat) would I need?

Thanks a lot!