Can I connect the (active) subwoofer and all my speakers though pcm and hdmi?

I have seen the option “hdmi multi ch pcm”, I thought that I can connect my subwoofer to pcm output and speakers though hdmi, but only the speakers work and the subwoofer not.
there is any option to make the swfr and speakers work simultaneously?

I have coreELEC version 9.2.1 on ODROID N-2.

Thank you!