To ammend what was said previously, yes, you unplug the hdmi cables for ten minutes, but you also unplug all the equipment as well for 10 minutes.
My understanding is that this "resets" the hdmi protocols in the equipment.
Why this fixed the subwoofers, i don't know, but it worked when the soft reset didn't.
Edit: I did not unplug the subwoofers, but i did unplug the tv, xbox, soundbar, and cable box.
Nakamichi recommends that you rehook up the hdmi back up from extremities to source. i.e., hook up the tv to soundbar, soundbar to xbox, xbox to cable box.
Last edited by PLANofMAN; 04-17-2019 at 08:06 PM.