The volume controller is indeed the tricky part.A more direct approach would be in hardware, over Bluetooth, which would be my preference as I prefer having a physical remote control, but then again a device like that could also drive a software based volume control.
I don't know which is the trickiest to design? An analogue volume controller which is as transparent as possible and which does not distort the signal, or a digital volume controller?
I guess the analogue one isn't a straightforward thing at all. As for the digital version, there's obviously Leedh Processing, which seems to be a good direction to take. But here too, good implementation requires creativity and skill. Which Taiko Audio has plenty of.
I bet you guys are havin' a lot of fun!

