To make the low brass sound, the player makes a buzzing sound by blowing air through closed lips. The mouthpiece amplifies the sound and it travels through the instrument's tubing and out through its bell. The player changes the pitch by pressing the valves in varied combinations or moving the slide in and out to make the different notes, increasing the length the sound must travel makes the note lower. The low brass family includes the baritone, euphonium, and tuba. Trombones are also in this family of low brass instruments, but we have another section just for them here!
The baritone is not the same as the euphonium. The baritone generally has a smaller bore size and a smaller bell than the euphonium. It also has cylindrical tubing, meaning that a person could remove the main tuning slide, rotate it and replace it backward.
The euphonium, on the other hand, has a larger bore and larger bell. They are also conical-bore instruments. This means that the tubing is almost constantly expanding from the mouthpiece to the bell. And 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, rich, and dark 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”.
The BBb tuba is considered the standard tuba in orchestras, bands, and brass ensembles. This instrument provides a vital chord 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 with 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 rotary valve design does not promote particularly fast response, but it includes a longer leadpipe, which contributes to a beautiful smooth tone that blends well with other instruments.
The “big brother” of the tuba family, the sousaphone is used almost exclusively in marching bands. Today they are produced in both brass and silver-plate for solid sound and projection, and lightweight fiber-reinforced plastic material to reduce fatigue during long performances. A combination of fiber/brass or fiber/silver-plate is also available. Most sousaphones have three valves, but some companies have introduced a four-valve sousaphone with much success.
You will find this feature on some professional euphoniums and tubas. This system enables the instrument to include the extremes of the low and high register while maintaining uniform tone quality and a stable intonation pattern throughout the playing range of the instrument. If a euphonium or tuba player wishes to be able to play a full chromatic scale in the lower register, a four-valve compensating system is the best answer. The 4th valve tubing routes back through the first 3 valves so that when the 4th valve is used in combination with any other(s), air can automatically be detoured through extra compensating loops. Essentially, this system improves intonation, especially in the lower registers.