In general, I’m not that concerned about keeping fingers close to instrument keys. A lot of woodwind players and teachers seem to believe that “close” fingers mean more speed, which I haven’t found necessarily to be the case. To me, a much larger factor is tension: if my fingers are tense (because, for example, I’m trying really hard to keep them close to the keys), they move more slowly.
But when I work with beginning clarinetists (whether first-time instrumentalists or doublers), many of them seem to have a great deal of trouble with squeaks and with notes responding sluggishly—problems that I think in most cases can be traced to fingers not completely covering toneholes, or not covering them in a synchronized way. And one of the major reasons that this happens is that the fingers are too detached from from the keys. It’s not a question of distance, per se, but one of awareness.
One reason this is such an issue for clarinetists in particular is that so many fingers have multiple jobs. The left thumb operates a tonehole/ring and a key, which must sometimes be pressed individually and sometimes together. The left index finger has a tonehole/ring and two keys. The right index finger has a tonehole/ring and four “side” keys. And the pinky fingers have responsibilities exceeded only by the bassoonist’s thumbs. Throw in a couple of sliver keys, and you’ve got a lot of fingers constantly in transit from one key to another.
Another reason is that the clarinet’s ring keys are fairly unforgiving compared to the plateau keys of a saxophone, an oboe, or some flutes (even “open-hole” flutes really only have small perforations in relatively large keys). The clarinet’s mechanism must be in good adjustment and the clarinetist’s technique must be precise in order to both operate each ring and fully close each underlying tonehole.
To develop a strong sense for where the keys and holes are located, I do encourage beginning clarinetists to keep the fingers not just close to the keys, but actually lightly brushing the rings. In the very earliest stages, I insist on this even at the expense of intonation, and, while their knowledge of pinky fingerings is limited to just one or two keys on each side, I have them keep those pinkies in constant contact with their respective keys. As they learn to use more keys, I have them practice moving the pinkies to the next needed keys as far in advance as possible, even several measures ahead, and then maintain contact. And as their mastery of the ring keys improves, they can learn to differentiate between close enough to the ring and too close to the ring (when the pitch is flattened and/or tone is muffled). Using these techniques from day one, they can quickly gain awareness of the keys’ locations. As they master this, I become far less picky about finger heights and instead encourage relaxed, freely-moving fingers. More advanced players whose fingers have gotten too free—to the point that accuracy suffers—can revisit these same techniques.
As a side note, the problems of squeaks and unresponsive notes, nearly always caused by imprecise finger technique, are too often met with bad advice like “tighten your embouchure” or “get a harder reed.” To educators and (shudder) the self-taught: check the fingers first. Then the fingers next. If problems persist, proceed to check the fingers one more time!