Review on Enhance Your Ride with the BOSS Audio MC420B Motorcycle Speaker System: Class D Amplifier, Weatherproof 3 Inch Speakers, Ideal for ATVs, Motorcycles & 12 Volt Vehicles by Mike Cody

I converted a Harley Road King into a trike and wanted to add some sound. Most of the speakers are mounted on the steering wheel, but I didn't really have room for them. Instead, I mounted them low on the rear fender mounts and facing forward. The quality is surprisingly good for the money. The amp is about the size of a large pack of cigarettes, and finding a place to mount it takes a little ingenuity. There are enough cables, but the excess has to be hidden under the seat etc. The Bluetooth connection works very well. I haven't tried the standalone MP3 plugin yet, but I assume it works too. It's just that I can barely hear them at high speeds, but part of that may be because I'm sitting in the back and looking ahead. My passenger should fit. In general, so far very happy with them.