How Does a Tuba Work?

A tuba is a big, funny-looking instrument that often gains a lot of laughs for its appearance. I’ll have to admit that whilst I’ve personally dabbled with just about every instrument I could get my hands on, the tuba has always eluded me. I always thought it was reserved almost exclusively for marching bands or comedy sketches. 

But after learning how a tuba is made and how sound is produced in one, I must admit I have a newfound respect for the instrument and appreciation of the sound it creates.

Before you understand how a tuba works, we’ll first look into just what exactly sound is. Then move on to how a tuba produces sound.

So let’s jump right in and take a brief look at how sound is made.

Photo by Brian Matangelo on Unsplash 

What Exactly Is Sound?

In the most simplistic of explanations, all sound is, is the movement of something on something else that we can hear. Sound is vibrations that travel through air (or some other medium) that can be heard when it reaches our ear. 

If you’ve never put your finger on a loudspeaker when it’s playing, doing so can help you get an idea of how it is that sound works. If the loudspeaker is playing a low note, you’ll even be able to see it vibrate. When the sound moves forward it compresses the air in front of it, raising its pressure. Some of this air flows outwards, compressing further levels of air. 

This disturbance in the air travels as a sound wave. It is this sound vibration that then causes our eardrums to vibrate. 

How Is Sound Made In A Brass Instrument?

Sound in a brass instrument is made from a vibrating column of air inside the instrument. To produce sound, a brass instrument player has to make their lips vibrate very quickly. When the player’s lips are placed against the mouthpiece, vibrations are sent into the instrument, forming sound waves. 

Depending on the length of the tube that the sound travels through, will dictate the pitch of the sound; whether it is low or high. On certain wind instruments like a trombone, for example, there’s a slide that either extends the tube where the air travels through, making the pitch higher or lower. 

Photo by Samuel Ramos on Unsplash 

Other instruments such as the trumpet, french horn and the tuba have valves. A trumpet usually has 3 valves whereas a tuba has between 3 and 6. Pressing down on these valves dictates how much air can pass through the instrument.

By tightening the lips, different notes can be produced on brass instruments. However, the range available to the player this way is fairly limited. To overcome this problem, valves were created to divert the airflow and cause it to travel through tubes of different lengths. 

Changing the length of the instrument changes the pitch of the note. The more tubing a flow of air has to pass through the lower the note will be. 

Once the air is vibrating within the instrument, some of that energy is radiated out as sound out through the bell. The column of air vibrates at certain frequencies much easier than at others (which is to say that it resonates at certain frequencies) these frequencies themselves often determine the playing frequency and the pitch.

The player can change the resonant frequency by changing the operating length of the instrument. Depending on the particular reed instrument, this is done in different ways, but the idea is the same; you insert extra lengths of pipe by using valves or in the case of the trombone, by using the slide. 

In the case of the tuba, valves are used.

Photo by Egor Myznik on Unsplash 

The Tuba

The word tuba was the name for the straight-built Roman trumpet and was the medieval Latin word for trumpet. The modern-day tuba is a deep-pitched brass instrument with a wide conical bore. It comes in a few different variations that are popular in different parts of the world.

The modern tuba was developed in the 19th century and contains about 16 feet of tubing. It is the deepest and lowest member of the brass section. They are commonly used in compositions that require a strong beat to be marked, such as in marches.

Tubas can be grouped into two or three varieties, depending on the type of valves used. There are piston tubas and rotary tubas. Piston valve tubas can be further classified into top action or front action tubas.

Top action tubas are popular in the UK and France. The pistons move vertically and are played with the fingers of the right hand. The bell rests on the players’ right side.

Top action tubas are the most prominent variety in the USA. On this kind of tuba, the pistons are positioned in front and are played with the right hand. The bell rests over the left of the player. 

Rotary valved tubas are most favored in Germany, Austrian, and Russia. The bell sits on the player’s left side and the levers are played by the right hand of the musician.  

The pitch of the instrument is also affected by the construction style of the particular instrument. 

The sousaphone is a relative of the tuba that was created by John Philip Sousa and has a slightly different shape. The sousaphone is popular for playing in parades and the like. 

Photo by David Vilches on Unsplash 

How Is Sound Produced In A Tuba?

 In a tuba, as in all other brass instruments, the airflow is controlled by the lips. When learning any brass instrument, the first thing you’ll be likely to learn is how to control how air passes out of your lips. You’ll be asked to close your mouth and pull your lips into a strange sort of smile. 

The more tension you apply to your lips, the quicker they spring back into place. With all other variables equal, high lip tension gives you a high frequency and so high pitch. The frequency of the lip vibration is the fundamental frequency of the note. 

To generate sound on a tuba, the human body is needed to act as a sort of resonance chamber. The vibration of the players’ lips in the cup-shaped mouthpiece and the flow of air from the player’s breath generate the sound in a tuba. The instrument needs resonance to amplify the sound.

What Are The Differences Between Piston and Rotary Valved Tubas?

Valves, whether they are rotary or piston are designed for changing the flow of air (breath.) They differ in how they affect the airflow angle when pressed. These design variations affect timbre and how easy it is to play slurs and other ornamentation to your playing, which is what gives your music your specific character and style.

How Does The Fingering On A Tuba Work?

The fingering on a tuba generally corresponds to other brass instruments like the trumpet for example. Relative to the tuba’s general pitch, low notes are plated by depressing the valves. Pressing valves extends the length of the tube. As previously mentioned, the greater the amount of tubing air has to pass through the lower the note will be. 

The first valve generally lowers the pitch by a whole tone the second valve lowers it by a halftone, the third by one and a half tones, and the fourth by two and halftones. 

Some tubas also have extra compensating valves to ease fingering, often using extended half of whole tones. 

To Sum Up

You’ll be forgiven for thinking of the tuba as little more than a joke of an instrument, reserved for clowns, comedy sketches, and military marching bands. Whilst tuba’s certainly do have a comedic effect due to their low pitch and clumsy appearance, they have more to offer than their pure comedy value. 

Sound effectively is just the vibration of matter on some medium that produces sound waves that are audible to us. A tuba works by the player introducing air into the instrument with their breath. This air then vibrates through the instrument and passes out of the bell. Depressing the valves lengthens the amount of tubing the air has to pass through, thus lowering the pitch of the sound. 

Tubas fill the important role of adding bass notes to brass sections, allowing balance to the higher brass instruments. Once we learn how sound is produced and the intricate mechanisms employed in the construction of the tuba, we can begin to move it out of the place reserved for comedy in our brains and into the area reserved for serious music-making and artistic expression (maybe.)

Leave a Reply