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Nov 09

The MyMusicTheory Guide to Orchestral Instruments; Part 3 – The Brass

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Brass Instruments

What are the standard orchestral brass instruments?

In a modern orchestra, you can expect to find the trumpet, French horn, trombone and tuba. In earlier times, for example when Mozart was composing (1700’s), only two trumpets and two horns were used. As the decades passed, composers wanted bigger, bolder sounds from their orchestras, and more brass instruments were added. In Beethoven’s later works (around 1800) it’s normal to find an additional two or three trombones, and three or four horns. By Wagner’s time (mid 1800’s) we find three trumpets and perhaps a bass trumpet, four to eight horns, three trombones and perhaps a contrabass trombone and four tubas! That’s a lot of brass!

sousaphone

Sousaphone

Other brass instruments which we don’t normally find in a symphony orchestra are the euphonium, sousaphone and cornet. They work in the same way as the trumpet etc., but are more commonly found in brass bands or military ensembles. Saxophones can be made of brass, but they are not classed as brass instruments because they use a reed to produce sound. What brass instruments have in common is not the actual material they are made of, but how they produce sound.

How do brass instruments work?

Trumpet mouthpiece

All brass instruments work in the same basic way. If you take a length of tube and make the air inside it vibrate, you will get a musical note. Brass players purse their lips against a cone-shaped mouthpiece to put pressurized air from their mouth into the tube, in order to make the air vibrate.

The pitch of the note produced depends on how much air there is inside the tube. The bigger the tube, the lower the note. So, a long, fat tube will make lower notes than a short, narrow one. The tuba is the lowest of the orchestral brass instruments, and the length of its tube is about 18 feet (5.5 metres).

If the player purses his lips a bit tighter, the air will be pushed into the tube at a higher pressure. The vibrations inside the tube will change, and so will the note that is played. With each increase in pressure, the player can sound the next note available from the length of tube. But what notes are available?

The notes which can be played on a simple length of tube are restricted to those which are part of something called the harmonic series. The lowest possible note (i.e. the one with the minimum air pressure) is called the fundamental. For example, the fundamental of a trumpet is C below middle C.

The fundamental note usually sounds pretty awful however, so it is not often used.

The next available note is one octave higher – middle C on the trumpet. This is called the first “overtone”. The first overtone is a clean sounding note and can be used in performance.

The second overtone is one perfect 5th higher than the first overtone – G on the trumpet.

Each overtone is closer than the previous one. Normally a good player can produce notes up to the 6th or 7th overtones. The higher the overtone, the more pressure is needed from the player’s mouth, and it gets progressively more difficult (and painful!) to play as the higher overtones are reached. The following staff shows the 7 basic overtones available on the trumpet. The Bb is in brackets because it is slightly out of tune.

harmonic series of the trumpet

 

 

Obviously, with such a small selection of notes to choose from, it’s quite difficult to play a melody on one tube. To get round this, ingenious musical instrument makers have invented some ways to increase the range of each brass instrument. There are two basic methods:

  • pistons or valves
  • slides

Pistons

The trumpet and tuba use pistons, and the horn uses valves – but both work in the same way. The tube of the instrument is coiled and looped, then fitted with three pistons. When the player presses a piston down, an extra loop of tubing is opened up. This has the effect of lengthening the entire tube, which means that a new, lower, fundamental note with a new harmonic series is now available. By combining the three pistons in different ways, six additional fundamentals can be achieved – on the trumpet, the fundamentals produced by each combination of pistons are:

  • no pistons (fundamental = C)
  • 2nd piston (B)
  • 1st piston (Bb)
  • 1st and 2nd pistons together (A)
  • 2nd and 3rd pistons together (Ab)
  • 1st and 3rd pistons together (G)
  • 1st, 2nd and 3rd pistons together (F#)

In the case of the trumpet, this enables the player to play all notes (including sharps and flats) from F# (below middle C) to the C two octaves above middle C.

The French horn often has a fourth valve – this has the effect of transposing all of the available pitches down by a perfect fourth, giving the horn a much wider range of notes than the trumpet.

Slides

trombone works with a slideThe trombone uses a completely different method to extend the range of available notes. You’ve no doubt seen a trombone player in action – the trombonist slides the end of the instrument up and down as s/he plays. As the player pulls the end of the instrument out, the length of tubing becomes longer. This in turn changes the fundamental note of the tube, and therefore the notes which are available based on the harmonic series.

Are brass instruments made of brass?

buy a trumpetYes, but not always! Modern brass instruments are made of  “yellow brass” which is made up of 70% copper and 30% zinc.

Some instruments are coated with lacquer. Gold and silver instruments are also available – at a cost!

The Yamaha trumpet pictured here is available from Musicroom.com.

Why are the trumpet and horn transposing instruments?

It’s helpful for a brass player to assume that the fundamental note of the instrument is C. That way, s/he can pick up any instrument of any size and the fingerings needed in order to play the higher notes will be the same. Trumpets actually come in all different sizes – you might find a trumpet in C, D, G or almost any key! The most common trumpet is in Bb – this means that when the player reads a note C, the actual note produced is a Bb. The trumpet in C is a bit smaller, and has a brighter tone.

The French horn, as mentioned above, sometimes has a transposing valve fitted. Basically this makes life easier for the player, who simply presses the valve down in order to extend the range of the instrument. Horns are usually in F, which means that an F is produced when the player reads a C. If the horn was not a transposing instrument, it would be a lot more complicated for horn players to read their music!

 

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2 comments

  1. Dave Harrison

    This is a useful primer, but I would suggest one correction. Playing higher on a brass instrument does requires a bit more pressure, but greater pressure on the mouthpiece is not the primary way of achieving this.

    The mechanism of how a mouthpiece and brass instrument is actually quite complex. The embouchure formed by the lips forms what may players call a “lip aperture”, though this is not truly an aperture in the sense of being a tiny hole. In fact the spot thought of as the aperture opens and closes at the frequency of the pitch being played on the horn. The resonance of the horn allows a standing wave to be formed at the pitches we all know are available on a brass instrument. There are two things that drive the brass player’s ability to control pitch: the tension or force in the lips and the mass of the vibrating portion of the lips. Ultimately, it is the vibrating mass that really controls things. The player controls the aperture size (hence the vibrating mass) and will need flexibility to do this. Pressure is not an efficient way to do this. Playing higher on a brass instrument should not be painful if proper technique is used.
    Cheers,
    Dave Harrison

    1. Victoria

      Thanks for the detailed comment!

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