Latest Gingerbread update messing with voice recognition on HTC EVO 4G
With the 4.24.651.1 Gingerbread update for the HTC EVO 4G, many things were fixed that the previous OTA had broken. But for some, along with those fixes came yet another problem: it can't hear you.
Well, the phone itself can, but the built-in speech recognition many times cannot make out what you're saying due to the microphone gain dropping to next-to-nothing. This issue pops up usually when you might need speech recognition, like while driving (and it's noisy), but will generally work when you're in a completely silent environment.
With rooting still off the table for anyone who accepted the OTA updates, the current workarounds being suggested are Vlingo or Edwin, neither of which use whatever parts are affected by the update.
According to a Sprint tech in the Sprint community forums, the problem is known and will be addressed in the next maintenance release; however, there is no ETA on that. This issue also does not appear to be solved by the steps in this thread, but you might want to give them a go while you wait for a fix and let us know if they work for you.