The clarinet register key and crossing the break
Almost every clarinet player hits the same wall: "the break." Notes below it feel comfortable, notes above it feel comfortable, but moving between them squeaks, cracks, or just doesn't come out. The break isn't a sign you're doing something wrong. It comes from how the clarinet is built. Once you understand it, you can practice your way across it.
How the register key works
The register key is the key on the back of the clarinet, pressed with your left thumb while your thumb also covers the thumb hole. When you press it, it opens a tiny vent near the top of the instrument. That vent makes the air column inside split into a higher vibration, so the same fingering plays a higher note.
For example, finger low E (all holes covered, with the low E key) and play it. Now add the register key without changing anything else. The note jumps up to a B in the middle of the staff.
Why it jumps a twelfth
On flute, oboe, and saxophone, the octave key (or overblowing) makes a note jump up an octave: low D becomes middle D, with almost the same fingering. On clarinet, the register key makes a note jump up a twelfth, an octave plus a fifth. Low E becomes B. Low F becomes C.
This happens because the clarinet's tube is cylindrical and acts as if it's closed at one end (by the reed and your mouth). A tube like that mostly produces odd-numbered overtones, and the first overtone available is a twelfth above the fundamental, not an octave. It's the same science that makes the clarinet sound darker and "hollower" than other woodwinds.
The practical result: fingerings in the upper register are different from the lower register. You can't just "add the thumb key and play the same fingering," as saxophonists can.
Chalumeau and clarion fingerings
| Register | Written range | How it works |
|---|---|---|
| Chalumeau (low) | Low E up to F♯ in the staff | Fingered without the register key |
| Throat tones | G, A♭, A, B♭ in the staff | Few fingers down, left hand keys |
| Clarion (middle) | B in the staff up to high C | Chalumeau fingerings plus register key |
| Altissimo (high) | Above high C | Special fingerings, advanced |
The break is the jump between the throat tones (around B♭, with almost no fingers down) and the clarion B (with almost every finger down, plus the register key). You go from nearly all holes open to nearly all holes closed in one move. That's why it's hard.
Twelfths to remember
- Low E + register key = B in the middle of the staff
- Low F + register key = C
- Low G + register key = D
- Low A + register key = E
Hand position for the break
- Cover every hole completely. Use the soft pads of your fingers, not the tips. A tiny leak on any hole is the most common cause of squeaks above the break.
- Keep fingers close. Hover just above the holes when they're up. Big finger movements make crossing slow and uneven.
- Roll, don't lift. For the A and G♯ keys, roll the side of your left index finger instead of lifting it off the tone hole.
- Keep your air and embouchure steady. Don't bite or pinch to reach higher notes. Fast, supported air does the work.
- Try keeping the right hand down. For throat tones, many teachers have students leave the right-hand fingers down. It barely changes the pitch, it helps the tone, and it means your right hand is already in place for the clarion notes.
Crossing-the-break exercises
1. Twelfth slurs
Play low E, then add the register key to slur up to B. Repeat with F to C and G to D. Keep the air moving through the change.
2. Top-down
Start on clarion C and slur down to throat B♭, then back up. Coming down first is often easier, and it teaches your hands the motion.
3. Right hand down
Play A to B with the right hand down the whole time. Only the left hand and thumb should move.
4. Slow and steady
Play a scale across the break (such as concert B♭ major, written C major; see concert pitch explained) as slowly as needed to keep every note clean. Speed comes later.
To learn the fingerings above and below the break, open Woodwind Trainer and choose clarinet. Use Key Builder to practice pressing the right keys for each note, including the register key, and Speed Match to recognize them quickly.