Well I changed my H/T setup a couple months ago and still haven't taken pics
The first version I just ran wire through a hole in the wall, this time I went with...
It required soldering the wire on the back and I simply drilled a hole in the drywall and used caulk to keep the piece in the hole. Definitely have painters tape ready to hold it in place and leave it for 24 hours.
I picked them up at a local shop (not the link) for $1 or so. They come in varying sizes but the one above I found easier to install as it has a lip to sit on the wall so it doesn't go through or too deep.
They aren't the prettiest but as long as they're covered....