I've had my PB2+ since the first of the year but due to some chronic family illness, we haven't been able to enjoy it loud as much as we did the 20-39pc that it replaced. Having kinda grown accustomed to the 20 hz response of the the pc, I just threw in one port block and set it to the 20 hz level and let her rip. As I said, we haven't been able to turn this monster up much at all but I did note that it wasn't as thunderous at the sweet spot as I thought it would be. Moving around the room showed me that it was definitely thunderous elsewhere but I am limited with placement so I just learned to live with it. My GFs illness has got somewhat better and allowed us to watch a few movies a little louder lately and I've got back into messing with my system more. The other night I got a wild hair and plugged another port and set the switch to 16hz. WOWOWOWOW... what a difference! Dramatic change in "pressure" at my sweet spot and my house is shaking a LOT more!!! It's hard to believe the difference that another port block made. It makes me wanna go back through my huge collection of movies that I bought just for the audio!!!