I have been watching with dismay some recent online message board conversations about clarinetists picking up the saxophone and saxophonists picking up the clarinet. I am of course a big supporter of doubling, but much of the discussion seems to center around embouchure, and the language used is not only misleading but also vaguely pejorative. Clarinetists seem to regard the saxophone embouchure as “loose,” a term I think most saxophonists would take exception to, and saxophonists consider the clarinet embouchure to be “tight,” a concept I would expect clarinetists to shy away from.
I am not aware of any difference in looseness/tightness between the embouchures of the two instrument families, and can’t think of a reason why there should be one. In both cases, the embouchure—the lips and surrounding facial muscles—need to be “tight” enough to form a non-leaking seal around the mouthpiece and reed, and “loose” enough to allow the reed to vibrate at the desired amplitude (volume). The most common looseness/tightness problem I see in teaching both instruments is excessive tightness, often used in an attempt to compensate for pitch stability problems caused by poor breath support, and resulting in sluggish response, restricted dynamic range, and stuffy tone.
The differences in the saxophone and clarinet embouchures are fairly minor and are mostly dictated by the size and angle of the mouthpiece (closer to vertical for clarinets—even large ones—and closer to horizontal for saxophones). The much more significant but frequently ignored issue is that of voicing. The clarinets, unique among the modern wind instruments, require a very high voicing, as though blowing cold air or pronouncing the long “E” vowel. The saxophones require a somewhat lower voicing, though not as low as flute and the double reeds, and with some variance depending on the size of the saxophone; this is closer to blowing warmish air and pronouncing the vowel in “word.”
The best way to solidify saxophone voicing is through mouthpiece pitch exercises. Pete Thomas has a nice article on mouthpiece pitch; I like his choices of pitches for soprano through baritone. I do think he sometimes says “embouchure” in the article when he is describing voicing, but he correctly emphasizes “tongue position,” which is what voicing is from an anatomical perspective. For the clarinet, I find mouthpiece pitch to be a less useful tool. A saxophonist hitting the right mouthpiece pitch is like a bowler picking up a single-pin spare, but a clarinetist’s all-the-way-to-one-extreme voicing is more like rolling the ball straight down the gutter—relatively easy in terms of aim.
A too-low voicing on clarinet produces the flat, tubby sound that is, unfortunately, the calling-card of the saxophonist who is a casual doubler. (Some insist that their “instrument” requires an unusually short barrel or a special mouthpiece in order to play up to pitch.) A too-high voicing, and a mouthpiece teetering on the very end of the cork, contributes to the pinched, thin tone and low-note difficulties that reveal the clarinetist sitting in the saxophone section.
Embouchure is important, but not the biggest issue in clarinet/saxophone doubling. Get a good teacher on each instrument, keep your breath support firm and your voicing accurate, and pay your dues in the practice room!