Low Brass
The Low Brass instruments make up the bass section of the orchestra.
The first two instruments, the baritone and the euphonium, are very similar but don't get them confused.
The baritone (pictured to the left) has a smaller bore size and a smaller bell than the euphonium. It also has cylindrical tubing, meaning that a person could remove a main tuning slide, rotate and replace it backwards.
The euphonium (pictured on the right) , on the other hand, has a larger bore and larger bell. They are essentially conical-bore instruments. That is, their tubing is almost constantly expanding from the mouthpiece to the bell. Also with conical tubing, the holes for the main tuning slide are not sized the same on the left and right sides. 
Baritones have a very light, bright sound that contrasts with the more powerful, richer, darker sound of the euphonium. Standard baritones and euphoniums have 3 valves. Intermediate to professional baritones and euphoniums will have 4 valves. The advantage of 4 valves is for the use of alternate fingerings on certain notes. Both also are available with front bells. In this configuration the bell faces forward rather than upward for improved projection and greater “presence”.
Like the trumpet, the main differences you will find between a student, intermediate and professional instrument are:
- Bore size
- Bell size
- Material used in the bell and the instrument
- Flare of the leadpipe and bell
- Manufacturing process
- Weight of the instrument
- Valves
Other differences:
- 3 valve (standard)
- 4 valve (intermediate/professional)
- 4 valve -compensating system (refer to tuba section for explanation)
- Upright vs. front bell
One of the most frequent questions among students and band directors is “What is the difference between the baritone horn and the euphonium?” In England, brass bands and military bands have used two different instruments. The baritone horn is the smaller of the two and is pitched in Bb. Although similar in appearance to the euphonium, the baritone has a smaller bore and a brighter, lighter tone quality. The euphonium is a larger bore instrument possessing a more powerful and richer tone quality. American instrument manufacturers have endeavored to combine the best qualities of the two instruments and the result is the baritone horn in general use in school bands today. These instruments are satisfactory for many occasions but lack the fullness and richness of the larger bore euphonium.
The addition of a 4th valve to the euphonium is very desirable as it not only expands the range of the instrument, but also can be used to improve intonation and facilitate certain technical passages. This 4th valve, when depressed, lowers the fundamental pitch from Bb to F. By using the 4th valve in conjunction with the other 3 valves, low notes below the bass clef can be played with ease and intonation in both the lower and upper registers may be corrected.
The word euphonium is derived from the Greek “euphonia” meaning “well-sounding,” and true to its name, the outstanding quality of the euphonium is its deep, rich tone quality. Too often the younger player will overlook the tone aspect of playing while striving for a flashy technical performance. Care should be taken to develop the proper embouchure and breath support to sustain a deep, rich, lush, smooth tone quality. Hand in hand with the development of a beautiful sound is the training of the ear and lips to overcome natural intonation deficiencies. The technical aspects of performance should be diligently worked out along with the tonal aspects so that the soloist may perform with ease the most demanding technical solo or passage while maintaining the rich quality of the more melodic parts. Far too many players devote themselves to one phase or the other while what is really needed is the well-rounded musician who is capable of performing all styles of music.
The BBb tuba (pictured to the left) is considered the standard tuba in orchestras, bands and brass ensembles. This instrument provides a vital chordal foundation in orchestras in addition to the low strings, and the main bass line in brass ensembles and bands. Tubas come in two sizes: ¾ size (for the smaller, beginning student) and of course the 4/4 size. 
They are also available in front action valves (valve caps face towards the front of the instrument), and top action valves (valves are located on the top of the body of the instrument and are operated in a vertical manner). Top action valves are the most popular.
The “big brother” of the tuba family, the sousaphone (pictured to the right) is used almost exclusively in marching bands. Today they are produced in both brass for solid sound and projection, and a lightweight fiber-reinforced plastic material to reduce fatigue during long performances. The main differences between a student, intermediate and professional tuba are basically the same as stated earlier in the baritone/euphonium section.
