Are you sure you don't have a "surround" or "stereo" option on the same page as the treble, bass, midrange page? Did you scroll down? It should be at the bottom of that page, and I would have thought both systems had it.
Either way, you should either change that center to an 8ohm speaker, or, if you're sure you're not getting any automation guidance from it, just disconnect it. But I would try all three and make sure you don't rob yourself of a feature. Try the Sync, Alexa, and OK-Google/Siri automation and make sure they aren't coming straight from the center.
Either way, you should either change that center to an 8ohm speaker, or, if you're sure you're not getting any automation guidance from it, just disconnect it. But I would try all three and make sure you don't rob yourself of a feature. Try the Sync, Alexa, and OK-Google/Siri automation and make sure they aren't coming straight from the center.