Main vs. sub panel for dedicated lines

I would also recommend grounding the ground to ground, and then grounding the Earth to ground. You never can be too sure, so I would ground all the grounds to all the pipes as well. Because, like, they go into the ground. 

Yeah, I know what you're thinking. There he goes being a a-hole again. But no, this actually is code now. The difference between all this BS everyone is so intent on doing, and what actually works, is so obvious if you could hear it that would be the end of that. But you can't. It is way too much work. You never in your life will do it to compare and know. That's why I did it. To know. Then comes the reason I hardly ever bother posting on the subject, https://youtu.be/9FnO3igOkOk?t=39

I am unclear as to what you are doing with this second home. If it really is a second home it would have its own service and panel. If you are running it off of your main panel then yes it would be a sub panel situation. If the listening room is in this second building then you would run the ONE dedicated listening room line to this sub panel.

Main thing is there be one dedicated line, and everything in the system uses this one line. All the lights and other outlets for accessories, you can run as many lines as you want for those. The system however, it all goes on one line.

The relevant comment from Michael Fremer starts at 15:50  https://youtu.be/H07NpWk_Xf8?t=950

Your dedicated LINE (singular, not plural) runs off the main panel.