A bass amplifier or "bass amp" is a musical instrument electronic device that uses electrical power to make lower-pitched instruments such as the bass guitar or double bass loud enough to be heard by the performers and audience. Bass amps consist of a preamplifier, tone controls, a power amplifier and one or more loudspeakers in a cabinet. While bass amps share many features with the guitar amplifiers used for electric guitar, they are distinct from other types of amplification systems, due to the particular challenges associated with low-frequency sound reproduction; this distinction affects the design of the loudspeakers, the size and design of the speaker cabinet and the design of the preamplifier and amplifier. Speaker cabinets for bass amps incorporate larger loudspeakers or more speakers and larger cabinet sizes than those used for the amplification of other instruments; the loudspeakers themselves must be sturdier to handle the higher power levels and they must be capable of reproducing low pitches at high sound pressure levels.
The bassists who first sought methods to make their instruments louder were upright bass players. While the upright bass is a large instrument, standing about six feet tall, due to its low register it is not a loud instrument when played acoustically, as lower frequencies attenuate with distance. In the 1890s and early 1900s, upright bass players performing in bars and brothels found it difficult to be heard by the audience over louder instruments such as trumpet. A partial solution was playing slap bass style, slapping the strings against the fingerboard to make a loud percussive sound. Beginning in the 1920s, the first amplifiers and speakers designed for gigging musicians became available. From the 1920s to the 1940s, upright bass players who wanted to strengthen the acoustic sound of their instrument had to use small portable PA systems or guitar amp combos designed for acoustic guitar or archtop guitars. Since these systems were not designed to amplify bass instruments, their utility was limited.
The only speakers available during the early 1920s were "radio horns of limited frequency range and low acoustic output," and the modern cone speaker was not available until 1925. The first amplifiers and speakers were PA speaker setups, were powered with large batteries, which made them heavy and hard to carry around. Engineers invented the first loud, powerful amplifier and speaker systems for public address systems and movie theaters; these were bulky and expensive, not intended to be transportable, so they could not be used by most touring and gigging musicians. After 1927, portable AC mains-powered PA systems "quickly became popular with musicians". Leon McAuliffe still used a carbon mic and a portable PA as late as 1935."During the late 1920s to mid-1930s, small portable PA systems and guitar combo amplifiers were similar. These early amps had a "single volume control and one or two input jacks, field coil speakers" and thin wooden cabinets, did not have tone controls or an on-off switch.
In 1928, Stromberg-Voisinet was the first company to sell an electric stringed instrument and amplifier package. However, musicians found that the amps had an "unsatisfactory tone and volume, dependability problems", so the product did not sell well, but set a new standard: a portable instrument amplifier with a speaker, all in an transported wooden cabinet. In 1929, Vega Electrics launched a portable banjo amplifier. In 1932, Electro String Instruments and amplifier introduced a guitar amp with "high output" and a "string driven magnetic pickup". Electro refined the standard template for combo amps: a wooden cabinet with the electronic amplifier mounted inside, a convenient carrying handle to facilitate transportion. 1n 1933, Vivi-Tone amp set-ups were used for live performances and radio shows. In 1934, Rickenbacker launched a similar combo amp which added the feature of metal corner protectors, which keep the corners in good condition during transportation. In 1933, Dobro released an electric amp package.
The combo amp had a five-tube chassis. In 1933, the Audiovox Manufacturing Company was founded by Paul Tutmarc, subsequently the inventor of the first electric bass, the fretted and solid-body Audiovox Model 736 Bass Fiddle, in 1936, designed to be played in a guitar-like horizontal manner; the instrument was sold with the first purpose-built bass amplifier, the Audiovox Model 936. Seen as a novelty, the few that were sold remained in the Seattle area; the Ampeg Bassamp Company, founded in 1949 by Everett Hull, responded to the growing demand for electric bass equipment by producing a line of bass amplifiers. The first model offered was the Super 800, an 18-watt model with a single 12" speaker and a rear ventilation port. In 1951, Ampeg introduced a 20-watt version with a 15-inch speaker. In 1960, they introduced the B-15 Portaflex, a flip-top 25-watt tube bass amplifier with a single 15" speaker. While the Portaflex had a pleasing bass tone, was used by studio bassists such as James Jamerson and Carol Kaye, it was not powerful enough to be used in a stadium or arena concert.
Ampeg amplifiers were used by electric bass guitarists in the 1950s and 1960s. Leo Fender resurrected the solid-body "bass guitar" in 1950 with the Fender Precision bass. Unlike the upright bass, a solid-body electric bass does not produce acoustic sound from a hollow body. By the late 1960s, as electric guitarists in rock ba
An effects unit or effects pedal is an electronic or digital device that alters the sound of a musical instrument or other audio source. Common effects include distortion/overdrive used with electric guitar in electric blues and rock music. Most modern effects use solid-state electronics or computer chips; some effects older ones such as Leslie speakers and spring reverbs, use mechanical components or vacuum tubes. Effects are used as stompboxes, which are placed on the floor and controlled with footswitches, they are built into amplifiers, tabletop units designed for DJs and record producers, rackmounts, are used as software VSTs. Musicians, audio engineers and record producers use effects units during live performances or in the studio with electric guitar, bass guitar, electronic keyboard or electric piano. While guitar effects are most used with electric or electronic instruments, effects can be used with acoustic instruments and vocals. An effects unit is called an "effect box", "effects device", "effects processor" or "effects".
In audio engineer parlance, a signal without effects is "dry" and an effect-processed signal is "wet". The abbreviation "F/X" or "FX" is sometimes used. A pedal-style unit may be called a "stomp box", "stompbox", "effects pedal" or "pedal". A musician bringing many pedals to a live show or recording session mounts the pedals on a guitar pedalboard, to reduce set-up and tear-down time and, for pedalboards with lids, protect the pedals during transportation; when a musician has multiple effects in a rack mounted road case, this case may be called an "effects rack" or "rig". When rackmounted effects are mounted in a roadcase, this speeds up a musician's set-up and tear-down time, because all of the effects can be connected together inside the rack case and all of the units can be plugged into a powerbar. Effects units are available in a variety of formats or form factors. Stompboxes are used units in live performance and studio recordings. Rackmount devices saw a heavy usage during the 20th century, due to their advanced processing power and desirable tones.
However, by the 21st century, with the advant of digital Plug-Ins and more powerful Stompboxes for live usage, the need and practicality of rackmounted effects units went down, as such, prices of rack effects have diminished due to lower usage. An effects unit can consist of a combination of the two. During a live performance, the effect is plugged into the electrical "signal" path of the instrument. In the studio, the instrument or other sound-source's auxiliary output is patched into the effect. Form factors are part of musician's outboard gear. Stompboxes are small plastic or metal chassis which lie on the floor or in a pedalboard to be operated by the user's feet. Pedals are rectangle-shaped, but there are a range of other shapes. Typical simple stompboxes have a single footswitch, one to three potentiometers for controlling the effect, a single LED that indicates if the effect is on. A typical distortion or overdrive pedal's three potentiometers, for example, control the level or intensity of the distortion effect, the tone of the effected signal and the volume of the effected signal.
Depending on the type of pedal, the potentiometers may control different parameters of the effect. For a chorus effect, for example, the knobs may control the speed of the effect. Complex stompboxes may have multiple footswitches, many knobs, additional switches or buttons that are operated with the fingers, an alphanumeric LED display that indicates the status of the effect with short acronyms; some pedals have two knobs stacked on top of each other, enabling the unit to provide two knobs per single knob space. An "effects chain" or "signal chain" is formed by connecting two or more stompboxes. Effect chains are created between the guitar and the amp or between the preamplifier and the power amp; when a pedal is off or inactive, the electric audio signal coming into the pedal diverts onto a bypass, an unaltered "dry" signal that continues on to other effects down the chain. In this way, a musician can combine effects within a chain in a variety of ways without having to reconnect boxes during a performance.
A "controller" or "effects management system" lets the musician create multiple effect chains, so they can select one or several chains by tapping a single switch. The switches are organized in a row or a simple grid. To preserve the clarity of the tone, it is most common to put compression and overdrive pedals at the start of the chain; when using many effects, unwanted noise and hum can be introduced into the sound. Some performers use a noise gate pedal at the end of a chain to reduce unwanted noise and hum introduced by overdrive units or vintage gear. Rackmounted effects are built in a thin metal chassis with metal "ears" designed to be screwed into a 19-inch rack, standard to the telecommunication and music technology industries. Rackmounted effects may be two or three rack spaces high; when purchased from the store, rack-mounted equipment is not equipped with the rugged chassis features used on
In theatre and performing arts, the stage is a designated space for the performance of productions. The stage serves as a space for actors or performers and a focal point for the members of the audience; as an architectural feature, the stage may consist of a series of platforms. In some cases, these may be temporary or adjustable but in theaters and other buildings devoted to such productions, the stage is a permanent feature. There are several types of stages that vary as to the usage and the relation of the audience to them; the most common form found in the West is the proscenium stage. In this type, the audience is located on one side of the stage with the remaining sides hidden and used by the performers and technicians. Thrust stages may be similar to proscenium stages but with a platform or performance area that extends into the audience space so that the audience is located on three sides. In theatre in the round, the audience is located on all four sides of the stage; the fourth type of stage incorporates created and found stages which may be constructed for a performance or may involve a space, adapted as a stage.
Since the Italian Renaissance, the most common stage used in the West has been the proscenium stage which may be referred to as a picture frame stage. The primary feature is a large opening known as the proscenium arch through which the audience views the performance; the audience directly faces the stage—which is raised several feet above front row audience level—and views only one side of the scene. This one side is known as the invisible fourth wall of the scene; the proscenium arch evolved from the proskenium in Ancient Greek theaters. This was the space in front of the skênê or backdrop where the actors played; the first indoor theatres were created in French tennis courts and Italian Renaissance palaces where the newly embraced principles of perspective allowed designers to create stunning vistas with buildings and trees decreasing in size toward a "vanishing point" on the horizon. Stage floors were raked upward from front to back in order to contribute to the perspective illusion and to make actors more visible to audiences, who were seated on level floors.
Subsequently, audience seating was raked, balconies were added to give audiences a fuller view. By the end of the 19th century most stages had level floors, much of the audience looked down on, rather than up to, the stage; the competition among royals to produce elegant and elaborate entertainments fueled and financed the expansion of European court theatres. The proscenium—which was decorative in the manner of a triumphal arch—"framed" the prospective picture; the desire of court painters to show more than one of their perspective backgrounds led court architects to adapt the pin-rails and pulleys of sailing ships to the unrolling, to the lowering and raising, of canvas backdrops. A wood grid above the stage supported pulleys from which wooden battens, steel pipes, rolled down, or descended, with attached scenery pieces; the weight of heavy pieces was counterbalanced by sandbags. This system required the creation of a storage stage house or loft, as high or higher than the proscenium itself.
A "full-fly" stage could store the entire height of scenery above the visible stage using the pin-rails before or during performance, whereas a "half-fly" stage could only store props of limited size and thus required more careful backdrop and scenery design. Theatres using these rope systems, which are manually operated by stage hands, are known as hemp houses, they have been supplanted by counterweight fly systems. The proscenium, in conjunction with stage curtains called legs, conceals the sides of the stage, which are known as the wings; the wings may be used by theatre personnel during performances and as storage spaces for scenery and theatrical properties. Several rows of short curtains across the top of the stage, called teasers, hide the backdrops, which in turn are hidden above the stage in the fly system loft until ready for use. A stage may extend in front of the proscenium arch which offers additional playing area to the actors; this area is a referred to as the apron. Underneath and in front of the apron is sometimes an orchestra pit, used by musicians during musicals and operas.
The orchestra pit may sometimes be covered and used as an additional playing space in order to bring the actors closer to the audience. The stage is raised higher than the audience. Space above some proscenium stages may include a flyloft where curtains and battens supporting a variety of lighting instruments may hang; the numerous advantages of the proscenium stage have led to its popularity in the West. Many theatrical properties and scenery may be utilized. Backdrops and lighting can be used to greater effect without risk of rigging being visible to the audience. Entrances and exits can be made more graceful; the actors only have to concentrate on playing to the audience in one direction. Boxes are a feature of more modern stage designs in which temporary walls are built inside any proscenium stage, at a slight angle to the original walls, in order to allow audience members located to the left or right of the proscenium to see the entirety of the stage, they enable the creation of rat runs around the back of the stage, which are when cast members have to walk between entrances and exits without being seen by the audience.
This type of stage is located in the centre of the audience, with the audience facing it from all sides. T
A rhythm section is a group of musicians within a music ensemble or band who provide the underlying rhythm and pulse of the accompaniment, providing a rhythmic and harmonic reference and "beat" for the rest of the band. Many of the rhythm section instruments, such as keyboard instruments and guitars, are used to play the chord progression upon which the song is based; the bass instrument plays the low-pitched bassline that supports the chord progression by emphasizing the roots of the chords. The term is common in modern small musical ensembles, such as bands that play jazz, country and rock. In modern rock music, a rhythm guitarist specializes in rhythmic and chordal playing repeating quaver, half note or whole note chords. In the louder genres, such as hard rock, heavy metal and punk rock, rhythm guitarists play power chords with distortion. Rhythm guitarists strum open chords in pop, rock and folk music and play barre chords in many pop and rock styles. A typical rhythm section comprises one or more guitars.
In some styles of music, there may be additional percussionists playing instruments such as the djembe or shakers. Some styles of music have two electric guitarists, such as rock genres like heavy metal music and punk rock; some styles of music use multiple keyboard instrument performers for a fuller sound. A rhythm section could be as small as two or three instruments or it may be a large ensemble with several keyboardists, several guitarists, auxiliary string players, a drummer and percussionists; the largest rhythm sections may be led by a bandleader or a conductor who indicates the tempo of each song, starts each song, leads slow-downs of the music at cadences, indicates when to change soloists and how and when the song will end. The instrumentalists used in a rhythm section vary according to the style of era. Modern pop and jazz band rhythm sections consist of a drummer, a bass player, one or more players of chordal instruments; the term rhythm section may refer to the instruments in this group.
In music industry parlance, the amplifiers and some of the instruments are nicknamed the "backline." Backline instruments are provided for bands at music festivals and other concerts where several bands will play during an event. By providing these backline instruments, this speeds up the changeover process when new bands take the stage; the backline includes large and heavy items that are hard to transport, including large bass amplifiers and guitar amplifiers and their speaker cabinets, the drum kit, a Hammond organ, stage piano, a keyboard amplifier. When a venue or festival provides a "backline", musicians must still supply some instruments themselves, such as guitars, an electric bass, and, in some cases, the cymbals and/or the snare drum; the venue informs musicians about which instruments are supplied as the backline for a specific concert or stage and in many cases, the contract signed by the band and the venue/promoter contains an explicit list of the backline gear that will be on stage specifying brand names and model numbers.
Although rhythm sections spend much of the time providing accompaniment for songs, in some cases, they provide other musical roles. In some songs or styles of music, instruments from the rhythm section may play soloistic roles on occasion or play a melodic role. Since rhythm sections are providing the background music for lead instruments and solo singers, rhythm sections are not as prominent as a singer or soloist, music fans tend to be more aware of lead singers than rhythm section members. However, since rhythm sections provide the underpinning for a good performance by the lead instruments and vocalists, good rhythm sections are valued in the music industry; some of the most accomplished rhythm sections have become famous, such as The Band, the E Street Band and Sly Dunbar and Robbie Shakespeare. As well, in some popular bands, all of the band members, including rhythm section members, have become famous as individuals. In all genres of popular music and traditional music that use rhythm sections, ranging from rock to country to jazz, the rhythm section members are expected to be able to improvise their parts or prepare their own parts for a given song by listening to the CD at home.
Once the bassist and chord-playing instruments are pro
An audio engineer helps to produce a recording or a live performance and adjusting sound sources using equalization and audio effects, mixing and reinforcement of sound. Audio engineers work on the "...technical aspect of recording—the placing of microphones, pre-amp knobs, the setting of levels. The physical recording of any project is done by an engineer... the nuts and bolts." It's a creative hobby and profession where musical instruments and technology are used to produce sound for film, television and video games. Audio engineers set up, sound check and do live sound mixing using a mixing console and a sound reinforcement system for music concerts, sports games and corporate events. Alternatively, audio engineer can refer to a scientist or professional engineer who holds an engineering degree and who designs and builds audio or musical technology working under terms such as acoustical engineering, electronic/electrical engineering or signal processing. Research and development audio engineers invent new technologies and techniques, to enhance the process and art of audio engineering.
They might design acoustical simulations of rooms, shape algorithms for audio signal processing, specify the requirements for public address systems, carry out research on audible sound for video game console manufacturers, other advanced fields of audio engineering. They might be referred to as acoustic engineers. Audio engineers working in research and development may come from backgrounds such as acoustics, computer science, broadcast engineering, acoustical engineering, electrical engineering and electronics. Audio engineering courses at university or college fall into two rough categories: training in the creative use of audio as a sound engineer, training in science or engineering topics, which allows students to apply these concepts while pursuing a career developing audio technologies. Audio training courses give you a good knowledge of technologies and their application to recording studio and sound reinforcement systems, but do not have sufficient mathematical and scientific content to allow you to get a job in research and development in the audio and acoustic industry.
Audio engineers in research and development possess a bachelor's degree, master's degree or higher qualification in acoustics, computer science or another engineering discipline. They might work in acoustic consultancy. Alternatively they might work in audio companies, or other industries that need audio expertise, or carry out research in a university; some positions, such as faculty require a Doctor of Philosophy. In Germany a Toningenieur is an audio engineer who designs and repairs audio systems; the listed subdisciplines are based on PACS coding used by the Acoustical Society of America with some revision. Audio engineers develop audio signal processing algorithms to allow the electronic manipulation of audio signals; these can be processed at the heart of much audio production such as reverberation, Auto-Tune or perceptual coding. Alternatively, the algorithms might carry out echo cancellation on Skype, or identify and categorize audio tracks through Music Information Retrieval. Architectural acoustics is the engineering of achieving a good sound within a room.
For audio engineers, architectural acoustics can be about achieving good speech intelligibility in a stadium or enhancing the quality of music in a theatre. Architectural Acoustic design is done by acoustic consultants. Electroacoustics is concerned with the design of headphones, loudspeakers, sound reproduction systems and recording technologies. Examples of electroacoustic design include portable electronic devices, sound systems in architectural acoustics, surround sound and wave field synthesis in movie theater and vehicle audio. Musical acoustics is concerned with describing the science of music. In audio engineering, this includes the design of electronic instruments such as synthesizers. Psychoacoustics is the scientific study of. At the heart of audio engineering are listeners who are the final arbitrator as to whether an audio design is successful, such as whether a binaural recording sounds immersive; the production, computer processing and perception of speech is an important part of audio engineering.
Ensuring speech is transmitted intelligibly and with high quality. A variety of terms are used to describe audio engineers who install or operate sound recording, sound reinforcement, or sound broadcasting equipment, including large and small format consoles. Terms such as "audio technician," "sound technician," "audio engineer," "audio technologist," "recording engineer," "sound mixer" and "sound engineer" can be ambiguous; such terms can refer to a person working in music production.
Audio power amplifier
An audio power amplifier is an electronic amplifier that amplifies low-power electronic audio signals such as the signal from radio receiver or electric guitar pickup to a level, high enough for driving loudspeakers or headphones. Audio power amplifiers are found in all manner of sound systems including sound reinforcement, public address and home audio systems and musical instrument amplifiers like guitar amplifiers, it is the final electronic stage in a typical audio playback chain before the signal is sent to the loudspeakers. The preceding stages in such a chain are low power audio amplifiers which perform tasks like pre-amplification of the signal, tone controls, mixing different input signals or adding electronic effects such as reverb; the inputs can be any number of audio sources like record players, CD players, digital audio players and cassette players. Most audio power amplifiers require these low-level inputs. While the input signal to an audio power amplifier, such as the signal from an electric guitar, may measure only a few hundred microwatts, its output may be a few watts for small consumer electronics devices, such as clock radios, tens or hundreds of watts for a home stereo system, several thousand watts for a nightclub's sound system or tens of thousands of watts for a large rock concert sound reinforcement system.
While power amplifiers are available in standalone units aimed at the hi-fi audiophile market of audio enthusiasts and sound reinforcement system professionals, most consumer electronics sound products, such as clock radios, boom boxes and televisions have small power amplifiers that are integrated inside the chassis of the main product. The audio amplifier was invented around 1912 by Lee De Forest, made possible by his invention of the first practical amplifying electrical component, the triode vacuum tube in 1907; the triode was a three terminal device with a control grid that can modulate the flow of electrons from the filament to the plate. The triode vacuum amplifier was used to make the first AM radio. Early audio power amplifiers were based on vacuum tubes and some of these achieved notably high audio quality. Audio power amplifiers based on transistors became practical with the wide availability of inexpensive transistors in the late 1960s. Since the 1970s, most modern audio amplifiers are based on solid state devices.
Transistor-based amplifiers are lighter in weight, more reliable and require less maintenance than tube amplifiers. In the 2010s, there are still audio enthusiasts, audio engineers and music producers who prefer tube-based amplifiers, what is perceived as a "warmer" tube sound. Key design parameters for audio power amplifiers are frequency response, gain and distortion; these are interdependent. While negative feedback reduces the gain, it reduces distortion. Most audio amplifiers are linear amplifiers operating in class AB; until the 1970s, most amplifiers were tube amplifiers. During the 1970s, tube amps were replaced with transistor-based amplifiers, which were lighter in weight, more reliable, lower maintenance. There are still niche markets of consumers who continue to use tube amplifiers and tube preamplifiers in the 2010s, such as with home hi-fi enthusiasts, audio engineers and music producers and electric guitarists, electric bassists and Hammond organ players, of whom a minority continue to use tube preamps, tube power amps and tube effects units.
While hi-fi enthusiasts and audio engineers doing live sound or monitoring tracks in the studio seek out amplifiers with the lowest distortion, electric instrument players in genres such as blues, rock music and heavy metal music, among others, use tube amplifiers because they like the natural overdrive that tube amps produce when pushed hard. In the 2000s, the Class-D amplifier, much more efficient than Class AB amplifiers, is used in consumer electronics audio products, bass amplifiers and sound reinforcement system gear, as Class D amplifiers are much lighter in weight and produce much less heat. Since modern digital devices, including CD and DVD players, radio receivers and tape decks provide a "flat" signal at line level, the preamp is not needed other than as a volume control and source selector. One alternative to a separate preamp is to use passive volume and switching controls, sometimes integrated into a power amplifier to form an integrated amplifier; the final stage of amplification, after preamplifiers, is the output stage, where the highest demands are placed on the transistors or tubes.
For this reason, the design choices made around the output device or devices, such as the Class of operation of the output devices is taken as the description of the whole power amplifier. For example, a Class B amplifier will have just the high power output devices operating cut off for half of each cycle, while the other devices o