Well, I've seen something like this before with an older BlackBerry, you could always tell when a call was coming through because any speaker around you that was turned on would go nuts.
We'll I'm having that issue with the Bionic, but it's not just when a call comes in, it's when the network fluctuates or when I recieve an email or text and sometimes just random.
I am using the desktop dock while I'm at work but the power source is near my radio and i have speakers hooked up to my computer. Sometimes it's so long and loud that I have to shut everything off or move my Bionic to the other side of my desk.
Anyone else get this?