I have the H700 and ever since I went from the curve to the tour my headset sounds terrible. To the point I can't understand people... It's to loud and distorted. I also have the Plantronics Voyager 510 and it doesn't seem to be any better with the tour.
It was perfect on the curve...
I am running 4.7.1.53 and yes tried changing all the bluetooth settings in the tour.
Ironically, I have the same headset and it works way better with the Tour than it ever did with the 8830. I have noticed that with the Tour, I don't need to turn the headset volume up nearly as high. It's usually arouond 50%.
I'm using a Motorola H715 I bought at Costco last year for around $60. It works great though I do have to turn it down because at its loudest settings it's way too loud. A good problem to have, I think.