This setting basically enhances privacy by encrypting calls. A voice message, in the case of Enhanced Privacy, requires an additional header and replaces some of the least important bits of the voice payload with the Initialization Vector. The replacement of payload bits reduces the voice quality. However, the reduction in voice quality is barely noticeable according to manufacturers. Anyway, I turned it off and I felt it improved my outgoing call quality a little bit. Voice sounded a little louder and fuller. Call still picks up some hiss/background noise due to insufficient noise cancellation though (but that's a hardware issue). I tested by recording a voicemail on my work phone. This logically should improve incoming call quality also. Anyone try this?