At first sight, voice changing might look easy to be implemented on a cell phone, but real time voice changing needs powerful chip sets that usually mobile phones does not have. This is why all voice changing services or applications are using external servers or external devices attached to a cell phone. Hence, no real security for phone user.

A voice changer is not really necessary when it comes to phone surveillance by law enforcement agencies: they know exactly your identity, location, call and message history, voice content of your calls and text content of your messages, etc. A voice changer gives you a false sense of security unless you intend to use it for a prank. In the last three years, interception systems that use the voice recognition function for automatic destination recognition and call recording have stopped being used as a primary filtering tool because the sample voice (needed for voice recognition) sounds different from phone to phone due to differences in hardware functions. This results in an undesirably high rate of false alarms.