I wanted a decent sound system for the front of the bus, to play music when the bus is in motion and stationary, and to make the GPS turn-by-turn directions coming from my tablet loud enough to hear over the roar of the engine. It might seem that the obvious choice was an in-dash car radio with an auxiliary input like this one. But these units include a radio tuner, which I wouldn’t use. And the only opening on dashboard to install it was to the left of the driver, making it awkward to use when the bus was stationary. So I decided to buy a stereo amplifier that would sit to the right of the driver. Last fall I installed two satellite speakers on the bulkhead over the windshield. They were driven by an underpowered amp temporarily duct taped to the dashboard. (Trashy, I know.) That amp died recently, and I replaced it with this more powerful one by Aiyima. There’s a lot to like about this unit, but unlike the old one, it requires 24-36 volts DC. The bus offers only 12 volts DC. So I used this voltage converter to convert 12 volts to 30 volts to power the amp. So far it’s working fine. The other issue with the new amplifier (that I would have noticed if I hadn’t shopped for it past my bedtime) is that it can drive a powered subwoofer, but not a passive one. So after a dead end trying to find a way to power the passive subwoofer I already owned, I gave up and bought this powered subwoofer. The installation is now complete. Click the image below to see the project unfold in episode 21 on my YouTube channel. And while you’re there, click the Subscribe button so you don’t miss subsequent episodes. Update: Below is a link to a short video in which I make a few refinements to the sound system, including adding soundproofing to the back of the subwoofer to eliminate a harsh noise: