Speaker wire is actually more prone to noise since it has no shielding, but it depends on the length of the run. In this case, it is after amplification though, so may be less of an issue, but the longer the run for amplified signal, the larger the wire you need to run too. For really long runs, you can use RG6 / 59 and use RCA terminations and it works fine. Speaker wire in wall needs to be UL rated.