There are few more coveted clarinet techniques than the smooth glissando, as heard in the famous opening to Rhapsody in Blue. But the technique isn’t intuitive, and lots of questions persist about how to do it.
(Incidentally: the Rhapsody in Blue score doesn’t call for a smooth portamento-type effect, but a scale with discrete notes. But the portamento became tradition early in the piece’s life and is now more or less required.)
How the clarinet glissando is done, technique-wise
One key thing to understand is that finger movement is the smallest part of the clarinet glissando. It’s not possible (or at least I’ve never seen it done) to achieve the full effect by simply uncovering toneholes gradually. The real work here is done with voicing.
Let’s break the technique down. We’ll use Rhapsody in Blue as an example, but the principles can be applied to other repertoire (or improvisations).
First, let’s look at what’s called for in the score:
Glissandos that cross register breaks are a particular challenge, so most clarinetists avoid that, opting to play a scale in the lower register, and beginning the glissando at the lower-clarion B or C.
High C is the destination note. Start by playing that note and using your voicing (think of blowing warmer air) to bend the pitch downward. Resist the urge to “lip” it down with your embouchure muscles or to let your breath support sag.
Bend it down absolutely as far as you can, until the note quits. It can take some practice to get a wide pitch bend range. Don’t strain; play around with it for a few minutes, then try again tomorrow.
Once you’re able to bend it fairly far, try kicking in some extra breath support. The air column is reluctant to vibrate when it’s bent too far (I’m fudging a little here on the acoustics). Use powerful air, even more powerful than usual, to make it keep vibrating, and see if you can bend even farther.
Now go to the lower part of the glissando, B or C in the staff. Try to bend it. You probably can’t bend this long-tube note, with lots of closed toneholes, nearly as much as you could bend the short-tube high C.
Now play the note, and gradually let your fingers lift, just a little bit, off the toneholes.
Notice that with the toneholes just slightly vented, the note becomes much less stable—or more bendable. Play around with the pitch to get the feel of it.
Now play the lowest note of the glissando (I’m using C here for simplicity). Move the fingers a little off their toneholes (all of them, except the left thumb, which stays in position for high C) while simultaneously bending the pitch down hard with voicing. (Remember to keep breath support strong.) While gradually moving the fingers farther off the toneholes, bend gradually upward with voicing. As the fingers finally completely clear the toneholes, the voicing arrives at its standard high position, and the pitch settles in on high C.
It takes practice to get the fingers and voicing coordinated, and to gain enough control to shape the bend just how you want it.
To execute the Rhapsody in Blue opening, play a scale in the lower register, then switch as seamlessly as possible to a glissando just above the register break. Some players play the scale portion as written, but some attempt to make it sound more glissando-like by turning it into a chromatic scale. Sometimes they also start the scale on chalumeau F-sharp rather than the written G.
How the clarinet glissando is done, taste-wise
Mastering the technique of the glissando, like mastering any technique, is only the first step. The next and perhaps more important step is to learn to do it with good musical taste.
When performing a glissando, carefully consider the shape of the pitch bend. How long is the bend overall? Should the pitch move in a straight line from one pitch to another? (Unlikely.) Should it have more of a curve, staying low at first and then rising at an increasing rate? Should there be a moment at the beginning or end at which the pitch remains stable, or is it constantly in motion?
These are fine distinctions, but important to the character of the glissando. Careful, detailed listening is crucial to the process—be sure to check out as many good recordings as you can, and note the differences in approach. If your intention is for the glissando to sound jazz-like, make sure you are listening to jazz players who use that effect, not just classical players who may or may not have done their homework.
Why it’s a clarinet-specific effect
The clarinet, unlike any of the other major modern wind instruments, uses a very high voicing for general playing. This leaves room to lower the voicing considerably for this special glissando effect. Flutes and double reeds (and brass instruments) use a very low voicing, which theoretically can be raised, but a raised voicing on a low-voicing instrument doesn’t cover as much territory pitch-wise; in other words, it’s harder to raise the pitch with voicing than it is to lower it. The saxophones, with an in-between voicing, have some flexibility here, but also have to contend with large keys on large toneholes, which are not as precise for hole-uncovering as fingertips on small clarinet toneholes. (The keys situation also explains why the larger clarinets aren’t nearly as agile with glissandos, even though those instruments are properly played with a high voicing.) In short, the technique lends itself particularly to the high clarinets, and may be much more difficult on other woodwinds.