Bass amplifier

A bass amplifier (also called a bass amp) is a special electronic device that helps make lower-pitched instruments, like the bass guitar or double bass, loud enough for everyone to hear. It uses electricity to boost the sound, so musicians and audiences can enjoy the music clearly.

Bass amps are different from regular guitar amplifiers because they need to handle very low sounds. This means they have bigger speakers, usually 15 inches or more, and stronger cabinets to support the sound. These amps also include parts like a preamplifier, tone controls, a power amplifier, and special loudspeakers that can handle more power and play very low notes.

Because low-frequency sounds can be tricky, bass amps are designed to be bigger and more robust than amplifiers for higher-pitched instruments like the electric guitar. This helps ensure that the deep, rich sounds of bass instruments fill a room perfectly during performances.

History

1920s–1940s

The first bass players to want louder instruments were those playing the upright bass. Even though this bass is large, standing about six feet tall, it does not produce loud sounds on its own because our ears are less sensitive to low sounds. In the early 1900s, bass players in bars had trouble being heard over louder instruments like trumpets. One way they dealt with this was by playing in a style called "slap bass," hitting the strings to make a louder percussive sound.

In 1933, a company named Audiovox was created by Paul Tutmarc, who later invented the first electric bass in 1936. This bass was sold with the first special bass amplifier, but only a few were sold and stayed mostly in the Seattle area.

1950s–1970s

The Ampeg Bassamp Company, started in 1949 by Everett Hull, made a line of bass amplifiers. Their first model, the Super 800, had an 18-watt power and a single 12-inch speaker. In 1951, they made a 20-watt version with a 15-inch speaker. By 1960, they introduced the B-15 Portaflex, a 25-watt amplifier that flipped open, used by famous bass players like James Jamerson and Carol Kaye.

Leo Fender introduced the solid-body electric bass guitar in 1950 with the Fender Precision bass. Unlike the upright bass, this electric bass needed an amplifier to be heard.

As rock bands in the late 1960s used louder amplifiers for big venues, bass players needed to keep up. The Acoustic 360, a 200-watt amplifier with an 18-inch speaker, helped prepare the bass world for big concerts like Woodstock. It was used by famous bassists such as Larry Graham, John Paul Jones of Led Zeppelin, and Jaco Pastorius.

Another popular amplifier from the 1960s was the Ampeg SVT, a 300-watt amplifier designed for use with large speaker cabinets.

The Vox T-60/AC-100 bass amplifier used two 15-inch speakers and solid-state power. The Sunn Model T was used by bands like The Moody Blues, Kiss, Queen, The Who, and Rush.

The Gallien-Krueger 800RB, introduced in 1983, was liked for its loud, clear sound and durability. It sent different levels of sound to bass and treble speakers. Famous users included Flea from Red Hot Chili Peppers and Duff McKagan from Guns N' Roses.

The Marshall JMP Super Bass, a 100-watt amplifier, was used by Lemmy of Motörhead. Fender also made the Fender Bassman in 1952, a 26-watt amplifier that became popular as both a bass and guitar amplifier.

In the 1960s, rock bands used PA systems mainly for vocals, so bass and electric guitar players used their own amplifiers. Some bass players used multiple amplifiers to get more volume. John Entwistle of The Who was one of the first to use powerful amplifier setups, influencing other bands.

1980s–2010s

In the 1980s, bass in music became more melodic. Trace Elliot amplifiers were known for their unique sound and features, like graphic equalizers and powerful amplifiers. As PA systems improved, better monitor systems allowed musicians to hear their instruments clearly on stage.

By the 2010s, bass players often used smaller amplifiers because PA systems could handle the sound for large venues. This made it easier for sound engineers to control the mix. In smaller venues, though, bass players still needed larger amplifiers to fill the space with sound.

Types

Different kinds of equipment are used to make bass instruments loud, depending on where and how the music is played. Professional bass players often have more expensive amps and cabinets. All bass amps and cabinets are made to be moved easily, with features like handles or wheels to help carry them.

Practice amps

The smallest bass amps are used for practicing alone in a small room. They aren’t loud enough for band rehearsals or shows, so they’re mostly used by beginners or for warm-up. Some of these amps can even run on batteries, which is useful for playing on the street.

Combo amps

For rehearsals, recording, or small club shows, bass players often use a “combo” amp. This combines everything—a preamplifier, tone controls, a power amplifier, and one or more speakers—in one cabinet. Smaller combo amps are easier to carry and set up, making them popular for many bass players.

Bass stacks

For big venues like stadiums or outdoor festivals, bass players often use a more powerful setup called a “bass stack.” This includes a strong amplifier and one or more separate speaker cabinets. Some players use different cabinets for different shows, like a bigger one for a stadium and a smaller one for a club.

Heads

Some bass amps don’t have speakers and are called “heads” or “amp heads.” These combine a preamplifier, tone controls, and a power amplifier in one unit. Using separate speakers lets players customize their setup and easily replace parts if something breaks.

Amplifier technology

Amplifiers can use different technologies, such as tubes (also called "valves") or solid state (using transistors), or a mix of both. Tube amplifiers were common in the 1950s and 1960s and are liked by some for their warm sound, but they need more care and are heavier. Solid state amplifiers became popular later because they are lighter, cheaper, and easier to maintain.

Hybrid amplifiers combine a tube preamplifier with a solid state power amplifier, giving the best of both worlds. The wattage of an amplifier affects its loudness, but doubling the power only makes a small difference in volume. Bass players usually need more powerful amps than guitar players to be heard clearly in a band. Most bass amps plug into a wall outlet, but some smaller ones can also run on batteries.

Loudspeakers

The lowest notes on a double bass or electric bass guitar can go very low, around 31 Hz to 41 Hz. To make these low sounds loud enough, bass amplifiers often use large speakers, usually 10", 12", or 15" in size. Sometimes, smaller speakers are used in groups, like two 10" speakers together. For even deeper bass, some players use special cabinets called subwoofers, which focus on very low frequencies.

Bassists sometimes add special speakers called tweeters to their setups for higher-pitched sounds. In the past, some used special cabinets with both regular speakers and tweeters, but today many clubs have systems that can handle the low sounds of a bass guitar. Using tweeters helps bass players add effects and play solos that highlight the higher notes of their instrument.

Cabinet design

Main article: Loudspeaker enclosure

To get the best low-frequency sounds, bass speaker cabinets often need to be larger. Most use a design with a special opening called a vent to help the speakers work better. Some cabinets have extra speakers that help with very low sounds. Most bass cabinets are shaped like a box, but some are wedge-shaped to make it easier for the player to hear themselves.

Tweeters

High-frequency speakers, called tweeters, are sometimes added to bass cabinets. In the past, some players used special setups with both regular speakers and tweeters, but today many clubs have systems that can handle the low sounds of a bass guitar. Tweeters help bass players add effects and play solos that focus on the higher notes of their instrument.

Controls, jacks and indicator LEDs

Controls

Bass amps have two main types of controls: switches and knobs. Simple practice amps might only have an "on/off" switch, a volume knob, and a bass and treble knob. More expensive models can have extra tone controls, like midrange knobs or a presence knob for high frequencies, and a second volume knob called "gain," "preamplifier," or "drive."

Some bass amps have multiple channels, each with its own settings. This lets a bassist prepare different sounds, like one for playing background music and another for a solo. In heavy metal bands, bassists might use one channel for a strong, distorted sound and another for a clean sound during slower songs.

On some amps, turning the "gain" or "drive" control too high creates a special sound effect. Higher-priced amps might have extra switches to adjust certain sound frequencies, like making the sound brighter or deeper. Some amps also have controls for protecting the speakers from sudden loud sounds.

Input and output jacks

Bass amps come with different input and output jacks depending on their price and purpose. The cheapest amps might only have one input jack. Some amps have extra inputs for connecting MP3 players or CD players for practice. Higher-priced amps for professionals often have an XLR DI output for connecting directly to a sound system or recording setup. Some amps also have a headphone jack for silent practice.

Indicator LEDs

The simplest amps might only have one light to show when they are powered on. More expensive amps can have extra lights to show when the instrument is connected, when the speakers are being protected, or when the amp is in standby mode.

Amplifying the double bass

Most bass amplifiers are made to work with an electric bass, which uses special magnetic pickups. For a double bass, the sound usually comes from a piezoelectric pickup placed on the bridge or under the bridge's feet. This pickup needs a preamplifier or a preamp-equipped DI box before the signal goes to the bass amp. The preamplifier helps make sure the signal works well with the amplifier, improving the sound. Some preamplifiers also have controls to change the tone.

Double bass players in styles where the bass is slapped, like traditional blues, rockabilly, psychobilly jazz, folk, and bluegrass, often mix the sound from a piezoelectric pickup with a small condenser microphone on the bridge. The microphone catches the sound from the body and the strings being played. The two sounds are mixed using a simple mixer and then sent to the amplifier.

Some jazz bass players and others in small places use special, expensive upright bass amps, like the Acoustic Image combo amplifier. In loud music styles like psychobilly, bass players might use "bass stacks." When playing loudly, double bass players might face a problem called audio feedback, which sounds like a loud, sudden howl and can damage speakers. To reduce this, some players use soft plastic discs to cover the sound holes or foam inserts in the "f" holes.

Preamplification and effects

The sound of a bass guitar or double bass can be changed using special effects. Because the bass usually helps keep the beat and rhythm in music, players often use a preamplifier and tools that control the loudness and balance of high and low sounds. These tools are called effect units.

Some bass players also use extra effects to make their instrument sound different, especially when they play solos. Effects like "wah-wah" and "fuzz" are popular in certain types of music. Some bass amplifiers even have these effects built right into them, so players don’t need extra pedals.

Manufacturers

Main article: List of bass amplifier and loudspeaker manufacturers

Many different kinds of companies make bass amplifier equipment. Some companies only make parts, while others only make the amplifiers and speakers themselves, like Gallien-Krueger. There are also big companies that make many types of equipment, including instrument amplifiers and public address systems, such as Peavey, Carvin A&I, and Yorkville Sound.

Some companies make equipment for everyday users, like Peavey and Yorkville. Others create special, high-quality equipment for professional musicians, such as Acoustic Image and Walter Woods. These special products are often used by musicians who play acoustic folk or jazz music.

Alternatives

Some bass players cannot use a regular bass amp because of noise rules, lack of space, or because they need to amplify more than just a bass. For those with noise or space limits, a headphone amplifier or a tiny practice amp with a headphone jack can be used. This lets the player practice without turning on the main speakers.

Players who need to amplify more than just a bass, like those who also sing or play other instruments, might use a keyboard amplifier, a small PA system, or special amplifiers for acoustic instruments that can also handle bass.

Even though some bass players have used regular guitar amplifiers for big shows since the 1960s, they usually still need a bass amp for the lowest sounds, because guitar amps cannot go low enough. One reason some players use both a bass amp and a guitar amp is to get a louder, overdriven sound from the guitar while keeping the deep bass tone.

Bass players without a regular amp can connect their bass to a DI unit and then to a PA system. In a well-equipped nightclub or music bar, the audio engineer can send the bass sound to a special speaker for the bass player. Some special preamplifier pedals also have a DI output for connecting to a PA system.

For small places like coffeehouses or small pubs, bass players usually need to bring their own amp because small venues often have very small sound systems mostly used for singing. In recording studios, bass players can connect to a DI unit, and the audio engineer can send the sound through headphones.