Course:Phys341 2020/Baritone ukulele

The Baritone Ukulele

Fig. 1. The four strings of the baritone ukulele, their notes, and their frequencies. Own Work.

The baritone ukulele, or simply the “bari,” is the largest instrument in the ukulele family. It has a larger body and longer neck than other ukulele sizes, which gives it a more resonant sound and a wider tonal range. The longer neck and the larger size of the bari makes it suitable for players with larger hands. The baritone ukulele can be thought of either as a smaller version of the guitar, or a larger version of the ukulele. Unlike regular ukuleles which are tuned to GCEA, the four strings of the bari are tuned a fourth down to DGBE (Fig. 1.), the same as the top four strings of a guitar. Because of this tuning, some players consider the baritone ukulele to be a miniature guitar, while others prefer to tune it back up to the regular GCEA tuning in order to attain a more classic ukulele sound.

History

The baritone ukulele was first created by Hawaiian instrument makers in the 1800s to emulate a Portugese machete. It was later sold commercially in the United States around 1950, and the credit for the American design is contested between guitarists Arthur Godfrey or Herk Favilla, both of whom developed the instrument around the same time. Godfrey commissioned another musician named Eddie Connor to design a larger, lower pitched ukulele. The resulting uke was put into production in the late 1950s in Massachusetts. Herk also developed his own ukulele in the 1940s. His design was intended to be a smaller version of the guitar for beginners. He began selling them through his family’s guitar store in the 1950s.

Construction

All ukuleles consist of a tuning mechanism, the neck and fretboard, and the body. While some baris are made from manufactured materials such as metal or plastic, most are made from timber. Ukuleles with faces made up of whole pieces of solid wood timber are more expensive and less durable, but have a more resonant sound. Other ukuleles used laminated wood for the sides and back end but still use a solid piece for the top, since this side has the most effect on the tone quality of the instrument. The type of timber used can vary greatly. Koa is a wood native to Hawaii, making it the traditional choice. Koa has a balanced and rich sound. Spruce, Mahogany, and Cedar are other common choices, and each alter the sound of the uke from bright to warm to sweet and mellow.

Fig. 2. The major parts of the baritone ukulele. Own Work.

General Characteristics

The construction of baritone ukuleles can vary, but the ukulele used for the creation of the following spectra (fig. 2.) has these characteristics:

Length: 30.5 inches

Scale length: 20 inches

Width at upper body curve: 7.75 inches,

Width at lower body curve: 10.25 inches,

Body Depth: 3.12 inches

Material of Top, Back, Sides, Neck: Mahogany,

Material of Fingerboard: Walnut

Material of Nut & Saddle: Plastic

String Material: Aquila Super Nylgut (Nylon + Gut)

String Gauges: E .0220 inches, B .0251 inches, G .0340 inches, D .0350 inches.

Fig. 3.1. Shape of a string plucked in the middle and the resulting harmonics. Own Work.

Fig. 3.2. Spectrogram showing the sound spectrum produced by plucking the middle of the G string. Own Work.

Acoustics

The ukulele is part of the lute family. Lutes consist of a resonating body with a light, resonant shell and a soundboard. The soundboard has a hole in it called the sound hole which effectively radiates lower resonances. The strings of a ukulele are stretched across the neck and are connected to the bridge, which is connected to the body. Once plucked, energy is input into the string, which causes the string to vibrate with a particular harmonic spectrum depending on the shape of the string (fig 3.1). The energy is then transferred via the bridge to the body, or the sound box, where certain harmonics are amplified, creating a specific sound spectrum (fig 3.2). The shape of the sound spectrum determines the timbre of the resulting sound. Sound waves are radiated to the listener through the sound hole, as well as through the soundboard.

Fig. 4.1 Primary Air Mode. Own Work.

Fig. 4.2 Primary Wood Mode. Own Work.

Fig. 5. Spectrogram showing the frequencies of the primary air and wood modes. Own Work.

Air and Wood Modes

When the energy of the strings is transferred to the body, the soundboard as well as the air inside the body begin to vibrate, creating two types of modes: the air mode of the sound hole and the wood mode of the sound board. In the air mode, the sound board and sound hole are vibrating in the opposite direction (fig 4.1), and most of the sound radiated from the instrument comes from the air in the sound hole. In the wood mode, they are vibrating in the same direction (fig 4.2), and most of the sound radiation comes from the soundboard itself. The air modes exist within the sound hole. The sound hole also gives rise to coupled oscillations at the lowest air and wood modes, allowing for a stronger resonant response at those frequencies. The frequencies of the strings that are near the resonant frequencies within the body of the ukulele are emphasized.

In fig. 5., the primary air and wood modes were found by muting the strings and tapping the bridge. The resulting spectrum shows the primary air mode at approximately 150Hz, and the primary wood mode at approximately 300Hz. The fundamental frequencies of the four strings of the baritone ukulele are all near the frequencies of the primary air and wood modes, resulting in a strong resonant response.

String or Mode	Frequency
D3	146.83Hz
Primary Air Mode	⩰150Hz
G3	196.00Hz
B3	246.94Hz
Primary Wood Mode	⩰300Hz
E4	329.63Hz