Monday, May 9, 2016

How Does a Brass Instrument Get Its Tone?

Learning about the many factors that affect a tuba’s tone will help you to improve your understanding of the instrument and basic acoustics. The tuba contains a series of brass tubes, welded together to create resistance, making it possible to successfully direct air through the horn. The tuba works through vibrations that turn into audible sound and become colored by the vibrations from the materials of the tuba.


All sound starts with a vibration that creates a pitch. These vibrations travel through the air causing the eardrum to transfer sound vibrations to the three small bones called ossicles in the middle ear. Vibrations occur anytime you hit, move or act upon an object by force. In the case of the tuba, the vibrations initiate from the vibrations of the lips.


The mouthpiece of the tuba makes it possible to focus sound through a quick stream of air that moves through the instrument. Mouthpiece materials play a large part in the timbre produced. Brass mouthpieces will create a strong, brassy tone while silver mouthpieces will create more mellow, soft tones. Steel mouthpieces produce stronger tones and gold will produce soft, supple tones. Plastic mouthpieces exist for extreme temperatures when playing outdoors, but should not be used for regular performances. The tubist learns specialist knowledge about what type of mouthpiece to use based on the music and environment.


The size and materials of the tuba have a major impact on the sound the tuba creates. Brass alloys, consisting of combinations of copper, nickel and zinc, create the materials used to mold tubing. Depending on the type and percentage of allows used, the tuba will have a different sound. Nickel gives the tuba a softer sound while copper gives the tuba more of an edgier brassy sound. The bending of the tubes makes it possible to use a reasonable amount of air to create sound. If the tubes didn't bend, air resistance would be minimal and it would create great difficulties in playing this large instrument. The resistance from the tubing makes it possible to play the tuba.


The bell's position directs the flow of sound into the room. For this reason, sousaphone bells on tubas will point directly forward. This helps ensure that the sound projects into the audience. Since a sousaphone performs outside, it is important to direct the sound forward so that it doesn't get lost. In concert halls, the tuba's bell will point upwards and be of varying diameters. Bells that have a narrow outwards flare and small diameter tend to have more precise sound. The bells that flare outwards with a larger diameter produce a great, booming tuba sound.