Convinced that playing the clarinet in a marching band was akin to squeezing a bicycle horn in front of a freight train, I happily volunteered to be the drum major all four years in high school.
The issue, though, is really “directional” vs. “cameral” sound. Brass instruments concentrate all the sound through the bell compared to only two notes on the clarinet; the rest mostly sound through the next open tone hole.
Clarinets are chamber (cameral) instruments—think of it as playing a mouthpiece attached to the room. The different acoustics of each room will affect your perception of your sound. But what do you do when the “room” has no walls?
Practice in many different places to get used to the sound of your instrument in various settings and the acoustics of different environments, i.e., studio, living room, garage, backyard and even the coat closet (which may take some explaining to your family). Make your sound a bit more directional by visualizing an external target at which to aim the stream.
You must always have a cushion of air welling up from your diaphragm to support a full, round sound. Test yourself: Stand up straight in front of the mirror and play a middle-of-thestaff B as pianissimo-ly as you can. If you’re supporting it correctly, those shades of purple that you are turning are normal. Since volume changes are really only the result of more air movement, take that air pressure you’ve built up and work at sending it through the horn.
Clarinets are relatively large bore instruments, but the opening between the reed and mouthpiece is relatively small, so you need to focus the air stream. You’ll need to “round out” your embouchure a bit by lowering your jaw (try mentally matching the bore of the clarinet). Keep the muscles tight around the sides of the mouthpiece, so your pitch and control remain intact, and your sound stays pure and focused.Remember: Bite not thine reed, as it’ll only constrict the air and the sound.
Practice these techniques physically and mentally with long tones. Then tell ’em to bring on the freight train!