Bass instrument amplification is normally regarded as distinct from other types of amplification system due to the particular problems of low frequency reproduction. This distinction mainly affects the loudspeakers used which tend to be larger than those used for other instruments. This is so that they can move the larger amounts of air needed in reproduction of low frequencies. In addition, human hearing is much less sensitive at lower frequencies, giving more need for higher volume levels to acheive the same loudness. Bass instrument amplification and sound reproduction is specialised due to the particular problems of low frequency reproduction. Loudness is the quality of a sound which is high in volume (amplitude, or sound pressure). ...

History

The 18 watt 1 x 12" Michael-Bell Bassamp, a closed-back amp designed specifically for upright bass, kicked off the modern era of bass amplification in the late 1940's. The upright basses were fitted with an Ampeg (short for "amplified peg") described in the 1946 patent application as a "sound amplifying means for stringed musical instruments of the violin family." In 1949, after the Michael-Hull company break-up, the Ampeg Bassamp Company was founded by Everett Hull in New York. Ampeg is an American instrument amplifier manufacturer. ...

Explanation

Bass amplifiers or 'heads' are usually charcterised by a lack of facilites that would be available on other instrument amplifiers (such as distortion, vibrato, echo, reverb etc) becuase they are generally not effecfive at low frequencies or do not enhance the sound.

Different types of equipment are used to amplify the electric bass and other bass instruments, depending on the musical setting. For rehearsals, recording sessions, or small clubs, electric bass players will typically use a "combo" amplifier. For larger venues, electric bass players will often use a more powerful amplifier (300 to 1000 watts) and separate speaker cabinets in various combinations.

2 x 10" stacked on top of a 15" cabinet, with separate head unit

bass amplifier stack An Acoustic 360 head with two Anthony Eden bass loudspeaker cabinets. ... bass amplifier stack An Acoustic 360 head with two Anthony Eden bass loudspeaker cabinets. ...

Categorization

Bass amplifiers may be categorized as either:

• combo units - the amplifier and speaker combined in a single unit; or
• head and speaker (or "cabinet") - amplifier and speaker are separate.

Combo units

For rehearsals, recording sessions, or small clubs, electric bass players will typically use a "combo" amplifier, so-named because it combines an amplifier and a speaker in a single cabinet. Combo amplifiers usually have a modestly-powered amplifer (50 to 200 watts) and a single speaker. The choice of amplification will have a significant impact on the bassist's overall sound.

Separates

Head units may, in turn, be either:

• integrated units, in which the preamplifier and power amplifier are combined in a single unit; or
• separate pre/power setups, in which one or more preamplifiers are used to drive one or more power amplifiers.

Technology

Amplifiers may be based on solid state (transistor) or thermionic ("tube" or "valve") technology. Tube amps are generally regarded as giving a warmer, more natural sound while solid state amps are lighter and lower maintenance, but this is an area of much debate. A common setup is the use of a tube preamplifier with a solid state power amplifier. There are also an increasing range of products that use digital modeling technology to simulate many different combinations of amp and cabinet choices. In physics, the solid state is one of the three phases of matter (solid, liquid, and gas). ... Thermionic emission is the flow of electrons from a metal or metal oxide surface, caused by thermal vibrational energy overcoming the electrostatic forces holding electrons to the surface. ...

Loudspeakers

The requirement to reproduce low frequencies at high sound pressure levels means that most loudspeakers used for bass guitar amplification are designed around large diameter, heavy-duty drivers, with 10", 12" and 15" being most common. As a general rule of thumb, performers desiring a deeper bass tone (e.g., punk, metal, or hard rock bassists) prefer the larger speakers, while performers wanting a more articulate tone (e.g. jazz or fusion bassists) tend to prefer the smaller speakers with a more extended mid range response. It has been suggested that this article or section be merged into Sound pressure. ... Closeup of a loudspeaker driver Wall-mounted loudspeaker. ...

The speakers are built into speaker cabinets, which contain one or more drivers. The sound of these cabinets is influenced not only by the choice of driver but also their construction. Bass speaker cabinets are either sealed or ported with tuned ports, openings designed to elicit a specific frequency response.

Speaker cabinets are largely designed around a single type of driver (common examples are 1X10" ,1x12", 1x15" and 2x10" or 4x10"). Bass players also stack two or more cabinets containing different-sized drivers to obtain a particular sound. Players with five- or six-string basses who perform in louder, heavier styles of music sometimes add a 1X18" cabinet to reproduce the lowest notes.

It is also increasingly common for high frequency "tweeters" or horns to be included in speaker cabinets. These extended range designs were initially developed in the late 1970s in response to the better quality pickups and electronics being built by Alembic and other high-end manufacturers and to better reproduce the more percussive bass playing styles that were becoming popular at the time. A Sony tweeter. ...

One problem with adding a horn to a speaker cabinet is that the horn may be damaged by the bass tone from an overdriven amplifier. Horns and speakers in the same cabinet are sometimes wired separately, so that they can be driven by separate amplifiers. Biamplified systems and separately-wired cabinets produced by manufacturers such as Gallien-Krueger allow bassists to send an overdriven sound to the speaker, and a crisp high sound to the horn, which prevents this problem.

Surveying the sites of the manufacturers mentioned below will give a good indication of the range of speaker cabinets currently available.

Preamplification and effects

Various electronic components such as preamplifiers and signal processors, and the configuration of the amplifier and speaker, can be used to alter the basic sound of the instrument. In the 1990s and early 2000s, signal processors such as equalizers, distortion devices, and compressors or [limiter]s became increasingly popular additions to many electric bass players' gear, because these processors give players additional tonal options. Signaling or signal may mean: Look up signal and signaling in Wiktionary, the free dictionary. ... For the British rock band of the same name, see Amplifier (band) An amplifier can be considered to be any device that uses a small amount of energy to control a source of a larger amount of energy, although the term today usually refers to an electronic amplifier. ... The word speaker has a number of uses: In politics the Speaker is the presiding officer in many legislative bodies. ... This article is about equalisers in mathematics. ... A distortion is the alteration of the original shape (or other characteristic) of an object, image, sound, waveform or other form of information or representation. ... Compressor has several meanings: A gas compressor is a mechanical device that takes in a gas and increases its pressure by squeezing a volume of it into a smaller volume. ... Fender Precision Bass Bass Guitar is a commonly spoken phrase used to refer to the electric bass and horizontal acoustic basses, a stringed instrument similar in design to the electric guitar, but larger in size, commonly fretted and sometimes fretless and with a lower range. ...

Effects

Because the electric bass plays the low-register foundation for the band, the so-called "modulation" effects, such as chorus, flanger, and phaser, are used much less frequently with the electric bass than with the electric guitar. Although there has been a much smaller variety of bass-specific effects available throughout much of the history of the instrument, since the late 1990's, many bass-specific effects have become available. Of these, preamplifiers, "compression", limiting, and equalization are the most widely-used effects for bass. Audio level compression, also called compression or limiting, is a process that manipulates the dynamic range of an audio signal. ...

Nonetheless, a range of other effects are used in various genres. "Wah-wah" and "synth" bass effects are associated with funk music. As well, since the 1960's and 1970's, bands have experimented with "fuzz bass" where the bass is distorted either by overdriving the amp or by using a distortion unit. Since the 1990's a heavier type of distortion with a "grinding" tone is used by some metal and punk bass players. Seventh release by Manchester indie rock group, James. ... Funk is a distinct style of music originated by African-Americans, e. ... A distortion is the alteration of the original shape (or other characteristic) of an object, image, sound, waveform or other form of information or representation. ... It has been suggested that this article or section be merged into Heavy metal music. ...

Although many of these effects sound similar to guitar effects, players often use specialized bass effects units, which are adapted to work with the lower frequency range of the bass. For example, typical electric guitar distortion units tend to remove the lower bass frequencies when they are used with an electric bass; bassists get much better results with a bass-specific distortion unit. For alternative and experimental bands, effects are used to create unique timbres and tones that in some cases are a radical departure from the typical electric bass tone.

Manufacturers of bass amplifiers or loudspeakers

include:

• Accugroove loudpeakers,
• Acme loudpeakers,
• Acoustic,
• Aguilar,
• Alembic (preamps and filters),
• Ampeg,
• Ashdown Engineering,
• Basson,
• Behringer,
• Crate,
• Eden Electronics, *Fender,
• Gallien-Krueger,
• Genz Benz,
• Hartke,
• Peavey,
• SWR,
• Markbass,
• Marshall,
• Mesa/Boogie,
• Orange, and
• Trace Elliot.