Alto Clef The two other clef signs are not used as often. Only the viola uses the Alto Clef. Both alto and tenor clefs are referred to as "C clefs". C clefs are moveable. They can be placed at any point on the staff. The center of the C clef indicates that this line is middle C. Another lesson later will also spend more time with note names on the "C clefs". This is an Alto Clef: This site was designed by This site is best viewed with an 800x600 Screen Resolution using Microsoft Internet Explorer. Copyright © 1999 D R Parman and Associates, Inc. - All Rights Reserved