Originally Posted by Chu Gai
You could use Romex but it's not a very good idea. It's not flexible, doesn't lend itself well to making appropriate connections, and is really suited best for high voltage applications. Just because you can use something, doesn't mean you should. After all, you could simply hook up your speakers using jumper cables. Wire that's in-wall rated is easy to find, reasonably priced, and won't suffer from the deficiencies that Romex has in this application.
hmm in wall requires flexibilty? To install and not really.
Suited for high voltage? Well yes, it is also suited for high amerpage as the function of the wire is not to turn cherry red.
Romex works fine. Just make sure it is of adequate guage for the power you are feeding the speakers and you are good to go. If you really want to get "omg" out of people, you could use normal electrical wire of adequate gauge to do the wiring. Really! Only important part is to get one of adequate gauge to not cause a fire