I received the email below today from Xtreme Revolution showing how they recommend modifying your UltraFairing to improve the amount of sound your stereo speaker output.
They have now added these additional instructions to their standard fairing (attached) installation guide.
UltraFairing Technical Bulletin Crank It Up!
You have recieved this email because our records indicate you have an Xtreme Revolution UltraFairing and we wanted to share this tip with you.
We have discovered a simple way to greatly increase the volume of the stereo in your UltraFairing. The problem is that the fairing is like a sealed drum, and for the speakers to move they actually have to compress the air in that sealed drum which steals away sound power. The solution is to create "tuned ports" for the fairing that allow the speakers to move freely. This is an old trick that has been used in speaker boxes for many years. If you create some tuned ports in the fairing you will notice a significant increase in the volume. The downside is that you will now have holes in the fairing -- bugs, mice, etc could get in. XR
See attached PDF file for images and instructions.