Hello and welcome to the forums - thanks for joining!
I am unsure of what your audio problems are... it is quite possible that they will be addressed by updating. Could you clarify on what issues you've been having and I'm sure that someone will be able to answer you.
If your phone has told you that there is an update, this would now update your phone from Sense 2.1 (I think) to Sense 3.0... the change is, by all accounts, quite good. The lockscreen will change and, I believe, a couple of the HTC apps also change.
I don't actually use Sense myself, but I'm sure that one of our other members will be able to give you a bit more info!