Decided to upgrade the sound system in R2. Instead of using the Bluetooth speaker I originally purchased when I was just using an iPod for the sounds, I went with regular speakers and an amp. Definitely a lot louder than the other speaker. Since the Padawan system has volume control, might as well have some range on the volume!
My plan is to mount the speakers directly behind each of the center vents. I glued two vertical pieces of styrene on either side of the uprights for the center vents. Tapped two screw holes on either side of the top and bottom vents to mount the speakers. I bought 3-1/2″ 100W Pyramid 312SX speakers for $15 on eBay.
To power the speakers I bought a Lepai 12V 2-chanel amp and a 3.5mm ground loop isolator noise filter on eBay for $22. I glued in two horizontal support pieces to hold the amp as shown in the picture.