The electric upright bass (abbreviated EUB and sometimes also called stick bass) is an electronically amplified version of the double bass that has a minimal or 'skeleton' body, which greatly reduces the size and weight of the instrument. The EUB retains enough of the features of the double bass so that double bass players are comfortable performing on it. While the EUB retains some of the tonal characteristics of the double bass, its electrically-amplified nature also gives it its own unique sound.
In comparison with other electronically-amplified string instruments, such as the electric violin, viola and cello, the EUB has been taken up by a wider range of players, perhaps because it is considerably easier to transport than its acoustic equivalent.
The scale length of EUBs varies: some scales are 42", similar to most double basses, whilst other models have scale lengths of only 30" like a short scale bass guitar. The shorter scale can make it easier for bass guitarists to convert to the EUB. Some scales lie between these two extremes. The fingerboard extends over two octaves and usually has side dots for the players reference. Regardless of scale length, the strings are usually tuned to E1, A1, D2, G2 (see Scientific pitch notation) at the same pitch as the double bass or bass guitar. Double bass players use features of the instrument such as the neck heel and edge of the upper bout as tactile positional references. The rear of the body of an upright bass is usually braced against the hip with player standing or knee if sitting. Many EUBs therefore mirror these features in their design.
There will often be a raised reference point about halfway down from the nut to the bridge at either the "D" or "Eb" position (where the notes "D" or "Eb" are found on the "G" string) to represent the 'neck heel' of the acoustic bass. Many EUBs have wooden or metal bars to brace the instrument against the musicians body, to act as the upper bouts of a wooden double bass. The wooden or metal brace bars help the EUB to rest against the player's body in a position roughly similar to the way a double bass rests against the body. The most complete example of this is the Yamaha 'silent bass' which has a removable frame designed to match the outline of right hand side and left upper bout of an upright bass allowing for easy transference of double bass techniques.
Solid bodied EUBs produce very little sound without electronic amplification. Hollow-bodied EUBs produce a quiet tone that is loud enough for individual practice. However, since hollow-bodied EUBs do not have a large resonant cavity like a double bass, they cannot reproduce the lowest notes of the instrument without an amplifier. To amplify the EUB, the string vibrations are sensed with a pickup. Early EUBs used magnetic pickups similar to those in electric guitars, or percussive magnetic diaghram pickups (e.g., the Ampeg Baby Bass). Many modern EUBs use piezoelectric pickups located in the bridge or a combination of pickup types. The signal from the pickup is usually preamplified and equalized with a preamplifier and then sent to a bass amplifier or a PA system. For practice in a hotel room or apartment, an EUB can also be connected to headphones.
Some EUBs have a hollow resonant chamber, such as the Eminence EUBs and some Aria and Azola models. While these small resonant chambers are usually not large enough to provide much acoustic amplification, they do change the tone and response of the instrument. Condenser microphones can be used to amplify EUBs with hollow bodies, often in combination with other types of pickups.
EUB players who use the bow need to use the appropriate pickup, microphone, and preamplifier/equalizer combination to avoid the tendency for the amplified tone to be scratchy and high-sounding. To obtain a more natural arco sound, some performers use a condenser microphone for arco passages. Most bass pickups are designed to capture the pizzicato sounds of a double bass rather than the arco sounds. Some pickup manufacturers produce piezoelectric pickups that purportedly provide a natural reproduction of arco sound. Preamplifiers and equalizers for acoustic instruments or double basses can also be used to "roll off" the treble frequencies or "notch out" the "scratchy-sounding" frequencies. An external parametric equalizer could also be used to remove unwanted "scratchy" sounds.
There are many varieties of EUBs available at present. Some EUBs cannot be used with a bow because of the large radius of the fingerboard and the flatness of the bridge. These types are therefore solely used for pizzicato playing. Other EUBs have a curved bridge which permits a bow to be used. EUB's are available in 4,5, 6 and 7-string models, and with solid, hollow and 'floating top' configurations. While hollow and 'floating top' models produce a more resonant tone, they are also more prone to feedback; as such, solid-body EUBs may be the best choice for bassists who play in loud styles, such as jam bands or metal fusion groups.
Like a double bass, the instrument may be played either standing or sitting on a tall stool. The optimum height for most players will be when the (index) finger in the first position (first fret on a fretted instrument) is at the same level as the player's eye. If the bass is higher than this, discomfort in the muscles of the neck may be experienced after playing long passages in the first position. If the bass is too low, the player may need to bend or stretch when attempting to play notes at the higher end of the fingerboard (although not as much as on a double bass). The strings are generally plucked with the sides of the top joints of the index and middle fingers, although sometimes the tips are used to produce a mellower tone or to facilitate rockabilly or bluegrass "slap" playing, while the thumb of the right hand rests against the side of the fingerboard. The strings are usually plucked over the fingerboard near the end. The left hand is used to stop the strings by pressing down with the fleshy part of the finger, generally using the ball of the thumb at the back of the neck to obtain pressure.
In the highest positions on the fingerboard, where the neck on an EUB gets considerably thicker, the left hand usage can be modified with the whole hand being brought round to the front of the instrument and the thumb taking the place of the index finger. These positions are called the 'thumb positions' in double bass parlance. In these positions, it is necessary to rest the neck of the bass against the players left shoulder in order to support the neck against the pressure of fingers on the strings. On the shorter scale EUBs, bass guitar fingering can be used over a large portion of the fingerboard and thumb positions may not be necessary. On the longer scale models, due to the larger distances between notes, the double bass (Simandl) fingering method usually has to be used unless the player has unusually large hands.
Since the EUB typically does not have a hollow sound chamber, or only includes a small sound chamber, the EUB is less prone to feedback than the double bass when amplified. To use a bow with an EUB, both the bridge and fingerboard need to be radiussed (given a curve). If the EUB's bridge and fingerboard are relatively flat, like those on an electric bass, then it is not possible to use the bow on the inner strings. By adjusting the amplifier tone controls an EUB can sound similar to an acoustic double bass. As well, by using tone controls and bass effects, an EUB can also take on a sound similar to a fretless bass guitar. Since the EUB transmits its sounds through a pickup, the tone is brighter than that of the acoustic double bass, which transmits its tone via the sound post to the back of the body. Compared to a double bass, the tone produced by an EUB is much less modified by its wooden 'body'.
In the 1990s and 2000s, Les Claypool used the EUB in several of his bands. Jeff Ament of Pearl Jam also regularly uses EUBs. Even in heavy metal, bassists such as Felipe Andreoli of Angra use EUBs; Andreoli uses a Brazilian-made D'Alegria instrument. Tony Levin plays an NS Electric Upright Bass, sometimes with pizzicato and sometimes with a bow. Italian bassist Don Bachi of Bandabardò regularly plays plucked EUB. Jazz musician Brian Torff uses EUB, often including percussion effects into his playing.