My 6610i ear piece sound quality seems pretty bad compared to my 8390. I can hear whitenoise in the earpiece while on a conversation and it sounds like if the Treble is cranked up to the maximum. At certain notes, the voice would crackle (similar sound is like if you push too much power to a tweeter).
My 8390 sounds solid and nice, no whitenoise no crackle.
Is it because of the codec? I'm using it on 1900mhz and the website indicates "AMR Voice Codec for 1900mhz".
I've tried the Full rate/half rate code but they don't work on 6610i.