A clarinet lyre is a handy metal holder that inserts between the clarinet's sections to hold a flip folder for sheet music. It commonly is used when a regular music stand cannot be used, such as in marching band or outdoor performances. Lyres for the clarinet are inexpensive and easily fit to the clarinet, but it may need some adjustment. If the lyre doesn't fit properly, the weight of the sheet music could cause it to flip sideways, so it's best to make it as tight as possible.
Separate the clarinet's upper and lower sections. In "The Clarinet and Clarinet Playing," by David Pino, these sections are "the upper joint (for the left hand) and the lower joint (for the right hand)."
Unscrew the metal ring at the base of the lyre, to make the ring larger.
Slip the ring part of the lyre over the metal rim of the clarinet's lower joint.
Tighten the screw, making sure the lyre is pointing straight out perpendicular to the clarinet, and the clip part is facing upwards.
Affix the upper joint of the clarinet to the lower joint. Test the lyre to make sure it is tight.
Assemble the rest of the clarinet.
You want the lyre as tight as possible, but not so tight it damages the clarinet's finish. Test the lyre before performing by clipping on a flip folder of sheet music.