I don’t have experience with the Eclipse, but if its anything like the newer TVs, if you unplug the 18s it will still function. HOWEVER – it will continue to send L/R audio to the 18s so you will no longer hear those channels. You’ll need to change the config in the Eclipse to send L/R to the built in speakers instead.
Slide the covers UP and then pull away. You need to remove the cover first to disconnect the cables.
There is a notched nut on the bottom of the wall mount. It comes with a special tool for removal, but it can probably be done with some small needle nose pliers (carefully!). Remove the nut and lock washer and lift the speaker out of the mount.
Procedure for mounting the speaker on the wall is up to you, but I would make sure they are mounted into wood (ideally studs) with some decent screws or lags. All of the weight is sent to the bottom, that’s a lot of leverage.
Backing for sound quality shouldn’t be a big deal, they are ported out of the front. Just make sure they are safely mounted.
