How to Turn Off Sound on a Samsung Galaxy S III for Specific Callers

You can create a silent audio file by opening the "Voice Recorder" app listed under the "Applications." Move to a place with as little ambient sound as possible during the recording process. Start the recording by tapping the "Record" icon and stop the recording by tapping the "Stop" icon. You need to record only about one second of empty audio. Voice Recorder will list all recorded audio files after you've finished recording; hold your finger on the silent recording to bring up the menu, select "Rename" and change the file name to "Silence."

Open the "Contacts" app and select the caller you want to silence. Tap the arrow icon under the "Ringtone" heading to bring up the "Ringtones" menu and select the "Add" option. Choose the "Sound Picker" option, select the "Silence" file from the "Songs" tab and tap "Done" to import the Ringtone and disable the contact's call sound. You do not need to import the silent audio file again and can change other contacts to the silent ring tone by selecting it from the "Ringtones" menu.