How to sing while playing clarinet

Last year, I spent a good deal of time learning a new-to-me skill for the world premiere of a solo work. My good friend Orlando Bass composed elleboro for solo clarinet, and each movement features various extended clarinet techniques, including singing while playing. I will be sharing a recording soon, and here is an excerpt from the movement which features this technique.

Singing while playing clarinet is an extended technique in which the player vocalizes a pitch while playing another note on the clarinet, creating a unique musical texture. Although I had heard this technique used before in other works, it’s not something I had previously attempted. I spent a significant amount of time learning and refining this technique, and now I really enjoy using it both as an extended technique and also as a warm-up to improve my voicing and pitch.

If you want to learn how to sing while playing, here’s what I did:

The biggest hurdle for me was getting used to singing while pushing air through the horn. Instead of thinking of this as singing, I like to imagine it as humming. Before attempting this technique on the clarinet, spend a few days singing/humming as you exhale and push air from your mouth.
At first, don’t focus so much on the specific pitches as on the act of producing a sung pitch while exhaling air through your mouth. It will be easier to refine your singing pitch after you become comfortable with this technique.
Once you are comfortable producing a sung pitch while exhaling, try to recreate this on the clarinet. Play an easy-to-produce note, such as open G or low C, and see if you can produce both the clarinet and sung note simultaneously. If you can’t do this, check to make sure you are using enough air speed and quantity to sound both.
Once you’re able to reliably produce both notes at the same time, begin to incorporate singing exercises while you play. I would practice exercises where the clarinet note was the drone, and I would sing in gradually expanding ascending and descending intervals (minor second, major second, minor third, major third, etc.).
Once you feel confident in your ability to sing while playing easier notes, repeat these techniques on a variety of clarinet pitches (higher and lower) to increase your flexibility with this technique.