Similar Material sg study 13 pp. 63-69 Voice Improvement and Use of Microphones Voice Quality Benefit From Theocratic Ministry School Education You Can Improve Your Voice Awake!—1970 What Does Your Voice Express? Awake!—1972 That Marvelous Gift—Your Voice Awake!—1984 Use of Microphone Benefit From Theocratic Ministry School Education Words Clearly Spoken Benefit From Theocratic Ministry School Education Voice Aid to Bible Understanding Voice Insight on the Scriptures, Volume 2 The Lungs—A Marvel of Design Awake!—1991 The Modern Marvel of Sound Amplification Awake!—1978