Live sound mixing is the blending of multiple sound sources by an
audio engineer
An audio engineer (also known as a sound engineer or recording engineer) helps to produce a recording or a live performance, balancing and adjusting sound sources using equalization, dynamics processing and audio effects, mixing, reproduction, ...
using a
mixing console
A mixing console or mixing desk is an electronic device for mixing audio signals, used in sound recording and reproduction and sound reinforcement systems. Inputs to the console include microphones, signals from electric or electronic inst ...
or software. Sounds that are mixed include those from instruments and voices which are picked up by
microphone
A microphone, colloquially called a mic or mike (), is a transducer that converts sound into an electrical signal. Microphones are used in many applications such as telephones, hearing aids, public address systems for concert halls and public ...
s (for
drum kit
A drum kit (also called a drum set, trap set, or simply drums) is a collection of drums, cymbals, and other auxiliary percussion instruments set up to be played by one person. The player ( drummer) typically holds a pair of matching drumsti ...
,
lead vocals
The lead vocalist in popular music is typically the member of a group or band whose voice is the most prominent melody in a performance where multiple voices may be heard. The lead singer sets their voice against the accompaniment parts of t ...
and acoustic instruments like
piano
The piano is a stringed keyboard instrument in which the strings are struck by wooden hammers that are coated with a softer material (modern hammers are covered with dense wool felt; some early pianos used leather). It is played using a keyboa ...
or
saxophone
The saxophone (often referred to colloquially as the sax) is a type of single-reed woodwind instrument with a conical body, usually made of brass. As with all single-reed instruments, sound is produced when a reed on a mouthpiece vibrates to pr ...
and
pickups for instruments such as
electric bass
The bass guitar, electric bass or simply bass (), is the lowest-pitched member of the string family. It is a plucked string instrument similar in appearance and construction to an electric or an acoustic guitar, but with a longer neck
The ...
) and pre-recorded material, such as
song
A song is a musical composition intended to be performed by the human voice. This is often done at distinct and fixed pitches (melodies) using patterns of sound and silence. Songs contain various forms, such as those including the repetitio ...
s on
CD or a
digital audio player
A portable media player (PMP) (also including the related digital audio player (DAP)) is a portable consumer electronics device capable of storing and playing digital media such as audio, images, and video files. The data is typically stored o ...
. Individual sources are typically
equalised to adjust the bass and treble response and routed to
effect processors
An effects unit or effects pedal is an electronic device that alters the sound of a musical instrument or other audio source through audio signal processing.
Common effects include distortion/overdrive, often used with electric guitar in ele ...
to ultimately be
amplified and reproduced via a
loudspeaker
A loudspeaker (commonly referred to as a speaker or speaker driver) is an electroacoustic transducer that converts an electrical audio signal into a corresponding sound. A ''speaker system'', also often simply referred to as a "speaker" or " ...
system. The live sound engineer listens and balances the various audio sources in a way that best suits the needs of the event.
Equipment
Audio equipment is usually connected together in a sequence known as the
signal chain
Signal chain, or signal-processing chain is a term used in signal processing and mixed-signal system design to describe a series of signal-conditioning electronic components that receive input (data acquired from sampling either real-time phenom ...
. In live sound situations, this consists of input
transducers
A transducer is a device that converts energy from one form to another. Usually a transducer converts a signal in one form of energy to a signal in another.
Transducers are often employed at the boundaries of automation, measurement, and contro ...
like
microphones
A microphone, colloquially called a mic or mike (), is a transducer that converts sound into an electrical signal. Microphones are used in many applications such as telephones, hearing aids, public address systems for concert halls and public ...
,
pickups, and
DI box
A DI unit (direct input or direct inject) is an electronic device typically used in recording studios and in sound reinforcement systems to connect a high-output impedance, line level, unbalanced output signal to a low-impedance, microphone level ...
es. These devices are connected, often via
multicore cable
A multicore cable is a type of electrical cable that combines multiple signals or power feeds into a single jacketed cable. The term is normally only used in relation to a cable that has more cores than commonly encountered. Not all cables with mu ...
, to individual channels of a mixing console. Each channel on a mixing console typically has a vertical "channel strip", which is a column of knobs and buttons which are used to adjust the level and the bass, middle register and treble of the signal. The audio console also typically allows the engineer to add
effects unit
An effects unit or effects pedal is an electronic device that alters the sound of a musical instrument or other audio source through audio signal processing.
Common effects include distortion/overdrive, often used with electric guitar in el ...
s to each channel (addition of
reverb
Reverberation (also known as reverb), in acoustics, is a persistence of sound, after a sound is produced. Reverberation is created when a sound or signal is reflected causing numerous reflections to build up and then decay as the sound is abso ...
, etc.) before they are electrically summed (blended together). A live audio sound mixer basically mixes a bunch of different signals together and then sends that blended signal to outputs (speakers).
Audio signal processing
Audio signal processing is a subfield of signal processing that is concerned with the electronic manipulation of audio signals. Audio signals are electronic representations of sound waves—longitudinal waves which travel through air, consisting ...
may be applied to (
inserted on) individual inputs, groups of inputs, or the entire output mix, using processors that are internal to the mixer or external (outboard effects, which are often
mounted in 19" racks). An example of an inserted effect on an individual input is patching in an
Autotune
Auto-Tune (or autotune) is an audio processor introduced in 1996 by American company Antares Audio Technologies. Auto-Tune uses a proprietary device to measure and alter pitch in vocal and instrumental music recording and performances.
Auto-Tu ...
rackmount unit onto the lead vocalist's track to correct pitch errors. An example of using an inserted effect on a group of inputs would be to add reverb to all of the vocalists' channels (lead vocalist and backing vocalists). An example of adding effects to the entire output mix would be to use a graphic equalizer to adjust the frequency response of the entire mix.
Types
Front of house mixing
The
front of house
In the performing arts, front of house (FOH) is the part of a performance venue that is open to the public. In theatres and live music venues, it consists of the auditorium and foyers, as opposed to the stage and backstage areas. In a theatre, t ...
(FOH) engineer focuses on mixing audio for the audience, and most often operates from the middle of the audience or at the last few rows of the audience. The output signals from the FOH console connects to a
Sound reinforcement system
A sound reinforcement system is the combination of microphones, signal processors, amplifiers, and loudspeakers in enclosures all controlled by a mixing console that makes live or pre-recorded sounds louder and may also distribute those sounds ...
. Other non-audio crew members, such as the
lighting console
A lighting control console (also called a lightboard, lighting board, or lighting desk) is an electronic device used in theatrical lighting design to control multiple stage lights at once. They are used throughout the entertainment industry and a ...
operator, might also work from the FOH position, since they need to be able to see the show from the audience's perspective.
Foldback
The foldback or monitor engineer focuses on mixing the sound that the performers hear on stage via a
stage monitor system
A stage monitor system is a set of performer-facing loudspeakers called monitor speakers, stage monitors, floor monitors, wedges, or foldbacks on stage during live music performances in which a sound reinforcement system is used to amplify a p ...
(also known as the ''foldback system''). The monitor engineer's role is important where the instruments and voices on the stage area is amplified. Usually, individual performers receive personalised feeds either via
monitors
Monitor or monitor may refer to:
Places
* Monitor, Alberta
* Monitor, Indiana, town in the United States
* Monitor, Kentucky
* Monitor, Oregon, unincorporated community in the United States
* Monitor, Washington
* Monitor, Logan County, West Vir ...
placed on the stage floor in front of them or via
in-ear monitor
In-ear monitors (IEMs) are devices used by musicians, audio engineers and audiophiles to listen to music or to hear a personal mix of vocals and stage instrumentation for live performance or recording studio mixing. They are also used by telev ...
s. The monitor engineer's console is usually placed in the
wings
A wing is a type of fin that produces lift while moving through air or some other fluid. Accordingly, wings have streamlined cross-sections that are subject to aerodynamic forces and act as airfoils. A wing's aerodynamic efficiency is expresse ...
just off-stage, to provide easier communication between the performers and the monitor engineer.
For smaller shows, such as bar and smaller club gigs, it is common for the monitors to be mixed from the front of house position, and the number of individual monitor mixes could be limited by the capabilities of the front of house mixing desk. In smaller clubs with lower- to mid-priced audio consoles, the audio engineer may only have a single "auxiliary send" knob on each channel strip. With only one "aux send", an engineer would only be able to make a single monitor mix, which would normally be focused on meeting the needs of the lead singer. Larger, more expensive audio consoles may provide the capabilities to make multiple monitor mixes (e.g., one mix for the
lead singer
The lead vocalist in popular music is typically the member of a group or band whose voice is the most prominent melody in a performance where multiple voices may be heard. The lead singer sets their voice against the accompaniment parts of the ...
, a second mix for the
backing vocalist
A backing vocalist is a singer who provides vocal harmony with the lead vocalist or other backing vocalists. A backing vocalist may also sing alone as a lead-in to the main vocalist's entry or to sing a counter-melody. Backing vocalists are us ...
, and a third for the
rhythm section
A rhythm section is a group of musicians within a music ensemble or band that provides the underlying rhythm, harmony and pulse of the accompaniment, providing a rhythmic and harmonic reference and "beat" for the rest of the band.
The rhythm sec ...
musicians). In a noisy club with high-volume rock music groups, monitor engineers may be asked for just the vocals in the monitors. This is because in a rock band, the guitarist, bassist and keyboardist typically have their own large amplifiers and speakers, and rock drums are loud enough to be heard acoustically. In large venues, such as outdoor festivals, bands may request a mix of the full band through the monitors, including vocals and instruments.
Drummers generally want a blend of all of the onstage instruments and vocals in their monitor mix, with extra volume provided for bass drum, electric bass and guitar. Guitar players typically want to hear the bass drum, other guitars (e.g., rhythm guitar) and the vocals. Bass players typically ask for a good volume of bass drum along with the guitars. Vocalists typically want to hear their own vocals. Vocalists may request other instruments in their monitor mix, as well.
Broadcast
The broadcast mixer is responsible for audio delivered for radio or television broadcast. Broadcast mixing is usually performed in an
OB van
A television production truck or OB van is a small mobile production control room to allow filming of events and video production at locations outside a regular television studio. They are used for remote broadcasts, outside broadcasting (OB), ...
parked outside the venue.
Sound checks and technical rehearsals
For small events, often a
soundcheck
A sound check is the preparation that takes place before a concert, speech, or similar performance to adjust the sound on the venue's sound reinforcement or public address system. The performer and the audio engineers run through a small port ...
is conducted a few hours before the show. The instruments (
drum kit
A drum kit (also called a drum set, trap set, or simply drums) is a collection of drums, cymbals, and other auxiliary percussion instruments set up to be played by one person. The player ( drummer) typically holds a pair of matching drumsti ...
,
electric bass
The bass guitar, electric bass or simply bass (), is the lowest-pitched member of the string family. It is a plucked string instrument similar in appearance and construction to an electric or an acoustic guitar, but with a longer neck
The ...
and
bass amplifier
A bass amplifier (also abbreviated to 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 audien ...
, etc.) are set up on stage, and the engineer places microphones near the instruments and amplifiers in the most appropriate location to pick up the sound and some instruments, such as the
electric bass
The bass guitar, electric bass or simply bass (), is the lowest-pitched member of the string family. It is a plucked string instrument similar in appearance and construction to an electric or an acoustic guitar, but with a longer neck
The ...
, are connected to the audio console via a
DI box
A DI unit (direct input or direct inject) is an electronic device typically used in recording studios and in sound reinforcement systems to connect a high-output impedance, line level, unbalanced output signal to a low-impedance, microphone level ...
. Once all the instruments are set up, the engineer asks each instrumentalist to perform alone, so that the levels and equalization for the instruments can be adjusted. Since a drum kit contains a number of drums, cymbals and percussion instruments, the engineer typically adjusts the level and equalization for each mic'd instrument. Once the sound of each individual instrument is set, the engineer asks the band to play a song from their repertoire, so that the levels of one instrument versus another can be adjusted.
Mics are set up for the
lead vocal
The lead vocalist in popular music is typically the member of a group or band whose voice is the most prominent melody in a performance where multiple voices may be heard. The lead singer sets their voice against the accompaniment parts of the ...
ist and
backup vocalist and the singers are asked to sing individually and as a group, so that the engineer can adjust the levels and equalization. The final part of the soundcheck is to have the
rhythm section
A rhythm section is a group of musicians within a music ensemble or band that provides the underlying rhythm, harmony and pulse of the accompaniment, providing a rhythmic and harmonic reference and "beat" for the rest of the band.
The rhythm sec ...
and all the vocalists perform a song from their repertoire. During this song, the engineer can adjust the balance of the different instruments and vocalists. This allows the sound of the instruments and vocals to be fine-tuned prior to the audience hearing the first song.
In the 2010s, many professional bands and major venues use digital mixing consoles that have automated controls and digital memory for previous settings. The settings of previous shows can be saved and recalled in the console and a band can start playing with a limited soundcheck. Automated mixing consoles are a great time saver for concerts where the main band is preceded by several support acts. Using an automated console, the engineer can record the settings that each band asks for during their individual soundchecks. Then, during the concert, the engineer can call up the settings from memory, and the faders will automatically move to the position that they were placed in during the soundcheck. On a larger scale, technical rehearsals may be held in the days or weeks leading up to a concert. These rehearsals are used to fine-tune the many technical aspects (such as lighting, sound, video) associated with a live performance.
Training and background
Audio engineers must have extensive knowledge of
audio engineering
Audio most commonly refers to sound, as it is transmitted in signal form. It may also refer to:
Sound
* Audio signal, an electrical representation of sound
*Audio frequency, a frequency in the audio spectrum
* Digital audio, representation of sou ...
to produce a good mix, because they have to understand how to mix different instruments and amplifiers, what types of mics to use, where to place the mics, how to attenuate "hot" instrument signals that are overloading and clipping the channel, how to prevent
audio feedback
Audio feedback (also known as acoustic feedback, simply as feedback) is a positive feedback situation which may occur when an acoustic path exists between an audio input (for example, a microphone or guitar pickup) and an audio output (for examp ...
, how to set the
audio compression for different instruments and vocals, and how to prevent unwanted
distortion
In signal processing, distortion is the alteration of the original shape (or other characteristic) of a signal. In communications and electronics it means the alteration of the waveform of an information-bearing signal, such as an audio signal ...
of the vocal sound. However, to be a professional live sound engineer, an individual needs more than just technical knowledge. They must also understand the types of sounds and tones that various musical acts in different genres expect in their live sound mix. This knowledge of musical styles is typically learned from years of experience listening to and mixing sound in live contexts. A live sound engineer must know, for example, the difference between creating the powerful drum sound that a
heavy metal drummer will want for their kit, versus a drummer from a
Beatles
The Beatles were an English rock band, formed in Liverpool in 1960, that comprised John Lennon, Paul McCartney, George Harrison and Ringo Starr. They are regarded as the most influential band of all time and were integral to the developme ...
tribute band
A tribute act, tribute band or tribute group is a music group, singer, or musician who specifically plays the music of a well-known music act. Tribute acts include individual performers who mimic the songs and style of an artist, such as Elvi ...
.
See also
*
Live event support
Live event support includes staging, scenery, mechanicals, sound, lighting, video, special effects, transport, packaging, communications, costume and makeup for live performance events including theater, music, dance, and opera. They all share th ...
*
Power Alley
*
Public address
A public address system (or PA system) is an electronic system comprising microphones, amplifiers, loudspeakers, and related equipment. It increases the apparent volume (loudness) of a human voice, musical instrument, or other acoustic sound sou ...
References
{{reflist
External links
FRONT of HOUSE MagazineStage Direction Magazine articles on sound designers for theatreAudio Engineering SocietyThe Acoustical Society of AmericaMix Magazine
Sound production technology
Audio mixing
Stagecraft