I think thatsome ofthe reasons that practicing long tones can be helpful
are as follows:
1. By eliminating all other factors such as fingers and tonguing, you can concentrate solely on tone production, which is a function of the balance of air and aperture. Striving for the most relaxed embochure
setting which will create a good sound at a given volume and velocity of air and listening for the tone with the most overtones and resonance is a very good discipline.
2. When we want to learn consisitency, the mind seems to learn best at an ultra slow pace. Long tones therefore help us to really know the feel and sound of each note, especially if you take the oppurtunity to see the note on the page, audiate the sound, think its name, feel it in the chops, etc.. The proper air speed and embouchure setting have a chance to become truly engrained. Eliminates guessing and just reaching for a note.
3. Use long tones to develop control of the air speed and aperture with crescedo/decrescendo exercises, being careful to stay in the center of the pitch at all times and to maintain a consistently good, clean sound.
4. Finally, moving to other notes, slurred, slowly, finding the resonant center of each pitch, especially when moving through the notes at the bottom and top of the staff, helps to create a uniform, centered tone.
My experience is that with 15-25 minutes a day of long tones, as a part
of your warm up, over a few months your sound will improve significantly,
You can wean down to 10 minutes over time because the skills that you
programmed through slow repetition become automatic.
I have to give credit to Jim Thompson, of the ASO, for helping me understand
how to use long tones effectively, He has published a book/tape called
Buzzing Basics which is a very ingenious adaptation of
Sclossberg, Stamp, Caruso type exercises. On the companion tape, available for C or Bb instruments, he demos each exercise and there is accompaniment throughout so that you will be sure to be playing in tune.
Very helpful when buzzing. It is available from the publishing side of the Atlanta Brass Society which can be reached at (404)875-TUBA.
Sorry to be so long winded!