Mmmm I wonder where that option would be?Perhaps you have some accessibility option on for the hard of hearing.
Thanks.... That was it. It must have either been on previously and not it did not show up or maybe came on by itself during the update. In any case I know it was not on bar before 2.3.4. I could have turned it on a long time ago trying to get a little extra volume out of the Sensation and forgot about it.That is the hearing aid icon. Go to your Call settings and turn it off. (Unless you're hearing-impaired and use hearing aides.)
P.S. As a side-effect, the hearing aid setting amplifies in-call volume. It may have been turned on by whomever borrowed or sold you the phone.