How Does That All Work? - Brass

  Have you ever been practicing or watching some of your "brass buddies" play around on their horns, and all of a sudden had an epiphany? You look at only a couple valves, but their all making a ton of notes. Isn't that just crazy...

How do brass instruments work?

  All instruments use some sort of vibration. Percussionists hit stuff, woodwinds blow through a reed, and brass players... we buzz. We blow air through our lip and create a vibration, a lot like how a woodwind blows through their reed. By speeding up, or slowing down, the air that passes by our lips is how we change the pitch.

  When you add a mouthpiece onto the lips it helps secure the buzzing area, and makes it easier to keep the buzz going. The mouthpiece also helps the sound of the buzz project better. When you add the horn onto the mouthpiece, you're not really changing that much. In simplest terms, the horn provides an even bigger amplifier to your original buzz, and the different slides and rotors help to center the pitches faster.

   Every brass instrument is basically just a long tube of metal. Our original buzz will create an air column that vibrates through the instrument. Every length of metal will vibrate at certain pitches just like how if you pluck a string it will make a certain sound; make the string shorter and the pitch will go up.

  Now what about all the different slides? As you press down a levers, or a piston, for a certain slide, you're adding that slide to the overall length of the instrument, lowering the pitch. Typically the first key adds whole step, the second will add a half step, and the third key will add one and half steps. Now certain instruments may have other ones at well that can add two whole steps, or even change the instrument to a different key; it all depends on which brass instrument you're talking about.

  If you're looking a brass instrument now and wondering, "I only see 3 or 4 different levers, how do you produce so many notes then?" that is normal. Like I said, "Every length of metal will vibrate at certain pitches..." This means that each different length of tubing in the instruments can produce countless different pitches.

 Every length of metal has a lowest pitch that it will naturally vibrate at, this is called the "fundamental pitch." (On a side note, the key of your brass instrument is usually decided by the pitch produced by the fundamental pitch: Trumpet in Bb, Horn in F, and so on...) If you speed the air up from this note the next note that will respond will be an octave. The next pitch that you'll reach will be a fifth higher, then a fourth. Is this starting to sound familiar? It should, this is the harmonic series, and for brass players: known as lip slurs. The harmonic series really never has an end to how high it can go, but as you go higher, the pitches will keep getting closer to together. For woodwind players, this is the same idea that's behind you're altissimo notes.

  Finally, if you think about it, this one length of metal can produce so many pitches. Now consider all the different combinations of slides lengths you can produce by using those different valves. Getting a little overwhelming? Well, by combining all these different aspects you get a full chromatic brass instrument that is capable of playing almost any Western music, just like our woodwind and string companions.