Can anyone advise if a radio flash is necessary on a 2017 CVO with Boom Audio II running three amps? My Bro just added a third amp to his bike to push the lower pod speakers. Problem is, the speakers aren't that loud, nor do they sound as clear as the fairing speakers. BTW, he did use the HD harness which even has one additional port to run a fourth Boom Audio II amp. Any insight from the pros would be greatly appreciated.