How do you play multiphonics on the french horn?

To play multiphonics on the French horn, a player must use a combination of specific fingerings and vocal techniques. This typically involves producing two or more pitches simultaneously by altering the embouchure and air support while using alternate fingerings or harmonics. Additionally, the player may also hum or sing while playing to create the desired multiphonic effect. Experimentation with different techniques and harmonics is key to achieving successful multiphonics on the horn.