Recently, one of my readers asked this question and this is the subsequent conversation:

Q: Several months ago I sent you a question asking about trombone embouchure and “firm corners”.  How firm should the corners be?  You mentioned that they should be “quite firm”.

As a pedagogical issue, I’m wondering about approaching this corner question a bit differently.  My question now is: Is it safe to say that by firming the corners, the player produces the lip cushion or pillow?  A trumpet teacher refers to the cushion as a “pillow”. In dealing with beginning brass players, I find it’s possible to “firm the corners” without producing the cushion, but it’s not possible to form the cushion, first, without “firming the corners.”  It’s seems a matter of where you place the focus, first.

I’ve spoken to several accomplished brass players, who also teach young students, and they mention continually having to remind their students to “firm the corners”, produce a “fish face”, but they’re not mentioning that this results in the lip cushion or pillow.

With beginning players, I have approached the cushion idea by asking students to produce a small ‘tube’ with their lips.  I do this by demonstrating a “quiet whistle” or ‘airy whistle’, not a ‘real’ whistle since that would place too much lip into the mouthpiece.  The “quiet whistle” produces an airy pitch and automatically sets up the oft-mentioned brass player’s face: firm corners and flat chin.  (Occasionally, a student’s quiet whistle will produce ‘white noise’ and not a pitch — I’ve always found that this is due to the lips being too tight.)  The ‘tube’ idea also works well for moving the air — another commonly heard instruction among brass teachers. Visualizing moving air ‘through the tube’ appears to increase relaxed air flow for many.

Jay: I don’t know about cushions and pillows. Everyone has their own way to think about embouchure. I keep it as simple as possible. If you want to spit air a long way you automatically firm the corners. I use the spitball test. Make a spitball and have someone spit it as far as they can. Watch the angle it travels. If it comes out low they need more corners. Most players need more corners to produce a sound that is lively and resonant with sufficient “core.”

Of course, the sound is the thing that judges the correct embouchure. The old idea of “spit some air into the horn” still is the best one because of the simplicity of concept. If a student can spit air without tightening the diaphragm, they will get a good sound. Thrust is achieved by building pressure behind sealed lips at the moment of departure. The torso will move but not tighten to start the air. I think of the lips like a rubber band that stretches and relaxes as the range changes. The more it stretches, the more air flow is needed, and the more mouthpiece pressure is needed. Physics says that for every action there is an equal and opposite reaction, hence the need for the “stability” of the mouthpiece to keep the embouchure still as more air and more tension in the corners need more stability from the mouthpiece.

Producing sound on a trombone requires three things that must be in near perfect balance: firm corners, sufficient air flow and sufficient mouthpiece stability or seal. Firm corners mean that every note should be thought of on a shelf. The embouchure should be thought of as a fork lift, delivering air to each level of the different levels of each shelf.
We don’t want any shelves that are not level and which sound can slide off. The embouchure and mouthpiece seal provide the necessary firmness to lift the sound to the highest shelves.

One important caution. I am firmly against free buzzing because without the mouthpiece to “lean against” the torso will tighten and the sound will constrict because SOMETHING must take up the reaction to the air flow forward and if it’s not the mouthpiece it will be the gut and THAT WRECKS THE SOUND.

Q: I think the feeling of pillow that the trumpet teacher mentioned is more pronounced because of the smaller trumpet mouthpiece.  Your spitball analogy is very good.  My first trombone teacher told me to “spit a seed off the end of your tongue”, but I found that this caused too much tension in the lips and resulted in more “buzz” than tone.  I think the “spitball” test solves this — gives a decent tone from the get-go.  Since beginners need something concrete to stay consistent, I think combining spitball with a straw (like a pea shooter idea) to direct air flow is useful.  I also agree with you about “free buzzing”.  I heard the late Bill Adam at Indiana U. mention this several times.