I have a XM Roady on my motorcycle. No other radio on cycle. As you probably know the XM Roady does not have a volume control. Currently using over the ear headset with volume control inline. I'm not getting enough volume coming out of the Roady to hear over the road noise. Need either amplifier (like Boostaroo, CMoy) or headset with inline amplifier. Headphones need to be either over or in the ear type or small enough to fit in my helmet and the amplifier must be very compact and reasonably water resistant. Any suggestions on what might work best?