I'm on the new firmware 4.13 and currently running Viper 4.0.0 though the issue started earlier when I was running Sin's Sense 5.5 rom. Before switching to Viper 4.0, I re-ran the firmware zips from Capt which wiped my internal sd and did a full wipe, but that didn't seem to help. I have not done the official HTC Ruu yet. I do not use PCs at home so I've not had access to a stable PC yet. That is the next thing on my list to try but I'm wondering if anyone else has experienced something similar.
I've tried cleaning the microphone holes, both the one at the bottom and the one at the top. It happens some times and not others which makes it hard to track down.
Thanks for any help!