Rapid single tonguing is one of the topics covered in depth by William R. Brophy in his Technical Studies for Solving Special Problems on the Horn. He offers a number of very specific suggestions on the topic.
Two things are necessary in fast tonguing. First, the tongue movement must be extremely small, and second (and probably even more important) the air pressure must remain behind the tongue for the duration of the tongued passage.
Here are some suggestions that may help in keeping the tongue movement small:
1. When the tongue withdraws to start the first note, be sure that it moves the smallest possible distance that will allow a free passageway for the air to enter the instrument.
2. Try to feel that the tongue is moving down and forward with the air stream instead of down and back against the compressed air. Whether or not this can be made to happen is debatable, to be sure, but thinking in these terms seems to be helpful.
3. Each time that the tongue returns to its position (usually against the back of the upper teeth) to stop one note in preparation for the start of the next, be sure that it is replaced with no more force than is necessary to stop the air for the shortest possible time—a length of time that would have to be measured in milli-seconds [sic]. Always think in terms of a clean, light attack.
The problem of making the air pressure work for us in rapid articulation, instead of against us, is not easily solved. Blowing a steady air stream … is a must, of course, but equally important is achieving the feeling of the tongue rebounding against the compressed air.
The principle is essentially the same as an air hammer of the type used to break up concrete. Just as the action of the air hammer is much faster than a sledge hammer, so the air pressure inside the mouth can be made to work for us instead of against us in rapid tonguing. This theory is readily proved by players who can tongue rapidly; these players can invariably tongue a series of notes more rapidly than they can say the syllables TATATATA. Obviously they have found a way to make the air pressure which is present in playing, but not in speaking, work for them.
Brophy notes that this happens “so rapidly that it almost defies analysis” but he attempts to explain the second principle above as follows:
1. The tongue is held lightly against the back of the upper teeth.
2. Air pressure is created behind the tongue by blowing.
3. The tongue is relaxed slightly so that the tension on it (especially the tip) is no longer sufficient to seal off the compressed air, which escapes through the small opening thus created, setting the lips into vibration and going ultimately, and coincidentally, into the horn.
4. As soon as this air escapes, the pressure within the mouth drops slightly as a consequence.
5. The slight tension held in the tip of the tongue is now sufficient, in the lessened air pressure, to return the tongue to its original starting place, stopping the air stream, allowing the air pressure to again build up so that the entire cycle can be repeated.
In this way the air pressure can be used to help, rather than hinder, the tongue action. If the tongue action can be thought of as a forward and downward action we can get the tongue to rebound against the stream of compressed air.
Rapid tonguing, overall, is yet another of those topics that with too much thought you can tie yourself up in knots but at the same time, if you can’t do it, you may need to give it more thought.
The Hornmasters are not done with tonguing topics yet. More soon.