Live sound mixing

Last updated February 16, 2024

Live sound mixing is the blending of multiple sound sources by an audio engineer using a mixing console or software. Sounds that are mixed include those from instruments and voices which are picked up by microphones (for drum kit, lead vocals and acoustic instruments like piano or saxophone and pickups for instruments such as electric bass) and pre-recorded material, such as songs on CD or a digital audio player. Individual sources are typically equalised to adjust the bass and treble response and routed to effect processors to ultimately be amplified and reproduced via a loudspeaker system.^[1] The live sound engineer listens and balances the various audio sources in a way that best suits the needs of the event.^[2]

Equipment

Audio equipment is usually connected together in a sequence known as the signal chain. In live sound situations, this consists of input transducers like microphones, pickups, and DI boxes. These devices are connected, often via multicore cable, 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 units to each channel (addition of reverb, 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).

EQ mixing involved adjusting each sound source's equalization (EQ) settings to achieve a desired sound. This involves adjusting the frequency, amplitude, and resonance of each sound source. EQ can be used to create clarity and depth to the mix, as well as to customize the sound of each instrument or voice.

Audio signal processing 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 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 (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. Other non-audio crew members, such as the lighting console 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 (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 placed on the stage floor in front of them or via in-ear monitors. The monitor engineer's console is usually placed in the wings 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, a second mix for the backing vocalist, and a third for the rhythm section 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.^[3]

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.^[3]

Broadcast

The broadcast mixer is responsible for audio delivered for radio or television broadcast. Broadcast mixing is usually performed in an OB van parked outside the venue.

Sound checks and technical rehearsals

For small events, often a soundcheck is conducted a few hours before the show. The instruments (drum kit, electric bass and bass amplifier, 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, are connected to the audio console via a DI box. 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 vocalist 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 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 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, how to set the audio compression for different instruments and vocals, and how to prevent unwanted distortion 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 tribute band. They should also be able to troubleshoot technical issues quickly and effectively, and be comfortable working with a variety of different systems and setups.

According to professionals,^[4] it is important to have both technical and creative skills. Technical skills involve understanding the principles of sound and acoustics, as well as being familiar with different types of audio equipment. This means understanding how to use equalization, compression, and reverb to create the desired sound.

Related Research Articles

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 instruments, or recorded sounds. Mixers may control analog or digital signals. The modified signals are summed to produce the combined output signals, which can then be broadcast, amplified through a sound reinforcement system or recorded.

<span class="mw-page-title-main">Recording studio</span> Facility for sound recording

A recording studio is a specialized facility for recording and mixing of instrumental or vocal musical performances, spoken words, and other sounds. They range in size from a small in-home project studio large enough to record a single singer-guitarist, to a large building with space for a full orchestra of 100 or more musicians. Ideally, both the recording and monitoring spaces are specially designed by an acoustician or audio engineer to achieve optimum acoustic properties.

<span class="mw-page-title-main">Multitrack recording</span> Separate recording of multiple sound sources to create a cohesive whole

Multitrack recording (MTR), also known as multitracking, is a method of sound recording developed in 1955 that allows for the separate recording of multiple sound sources or of sound sources recorded at different times to create a cohesive whole. Multitracking became possible in the mid-1950s when the idea of simultaneously recording different audio channels to separate discrete "tracks" on the same reel-to-reel tape was developed. A "track" was simply a different channel recorded to its own discrete area on the tape whereby their relative sequence of recorded events would be preserved, and playback would be simultaneous or synchronized.

Dynamic range compression (DRC) or simply compression is an audio signal processing operation that reduces the volume of loud sounds or amplifies quiet sounds, thus reducing or compressing an audio signal's dynamic range. Compression is commonly used in sound recording and reproduction, broadcasting, live sound reinforcement and some instrument amplifiers.

A DI unit is an electronic device typically used in recording studios and in sound reinforcement systems to connect a high output impedance unbalanced output signal to a low-impedance, microphone level, balanced input, usually via an XLR connector and XLR cable. DIs are frequently used to connect an electric guitar or electric bass to a mixing console's microphone input jack. The DI performs level matching, balancing, and either active buffering or passive impedance matching/impedance bridging. DI units are typically metal boxes with input and output jacks and, for more expensive units, “ground lift” and attenuator switches.

A public address 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 source or recorded sound or music. PA systems are used in any public venue that requires that an announcer, performer, etc. be sufficiently audible at a distance or over a large area. Typical applications include sports stadiums, public transportation vehicles and facilities, and live or recorded music venues and events. A PA system may include multiple microphones or other sound sources, a mixing console to combine and modify multiple sources, and multiple amplifiers and loudspeakers for louder volume or wider distribution.

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 to a larger or more distant audience. In many situations, a sound reinforcement system is also used to enhance or alter the sound of the sources on the stage, typically by using electronic effects, such as reverb, as opposed to simply amplifying the sources unaltered.

An aux-send is an electronic signal-routing output used on multi-channel sound mixing consoles used in recording and broadcasting settings and on PA system amplifier-mixers used in music concerts. The signal from the auxiliary send is often routed through outboard audio processing effects units and then returned to the mixer using an auxiliary return input jack, thus creating an effects loop. This allows effects to be added to an audio source or channel within the mixing console. Another common use of the aux send mix is to create monitor mixes for the onstage performers' monitor speakers or in-ear monitors. The aux send's monitor mix is usually different from the front of house mix the audience is hearing.

A DJ mixer is a type of audio mixing console used by disc jockeys (DJs) to control and manipulate multiple audio signals. Some DJs use the mixer to make seamless transitions from one song to another when they are playing records at a dance club. Hip hop DJs and turntablists use the DJ mixer to play record players like a musical instrument and create new sounds. DJs in the disco, house music, electronic dance music and other dance-oriented genres use the mixer to make smooth transitions between different sound recordings as they are playing. The sources are typically record turntables, compact cassettes, CDJs, or DJ software on a laptop. DJ mixers allow the DJ to use headphones to preview the next song before playing it to the audience. Most low- to mid-priced DJ mixers can only accommodate two turntables or CD players, but some mixers can accommodate up to four turntables or CD players. DJs and turntablists in hip hop music and nu metal use DJ mixers to create beats, loops and so-called scratching sound effects.

A bass amplifier 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 typically consist of a preamplifier, tone controls, a power amplifier and one or more loudspeakers ("drivers") in a cabinet.

<span class="mw-page-title-main">Digital mixing console</span> Electronic device used to manipulate audio input signals using digital signal processing

In professional audio, a digital mixing console (DMC) is a type of mixing console used to combine, route, and change the dynamics, equalization and other properties of multiple audio input signals, using digital signal processing rather than analog circuitry. The digital audio samples, which is the internal representation of the analog inputs, are summed to what is known as a master channel to produce a combined output. A professional digital mixing console is a dedicated desk or control surface produced exclusively for the task and is typically more robust in terms of user control, processing power and quality of audio effects. However, a computer can also perform the same function since it can mimic its interface, input and output.

Stem-mixing is a method of mixing audio material based on creating groups of audio tracks and processing them separately prior to combining them into a final master mix. Stems are also sometimes referred to as submixes, subgroups, or buses.

<span class="mw-page-title-main">Stage monitor system</span> Sound reinforcement for performers

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 performance for the audience. The monitor system allows musicians to hear themselves and fellow band members clearly.

An audio engineer helps to produce a recording or a live performance, balancing and adjusting sound sources using equalization, dynamics processing and audio effects, mixing, reproduction, 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."

In sound recording and reproduction, audio mixing is the process of optimizing and combining multitrack recordings into a final mono, stereo or surround sound product. In the process of combining the separate tracks, their relative levels are adjusted and balanced and various processes such as equalization and compression are commonly applied to individual tracks, groups of tracks, and the overall mix. In stereo and surround sound mixing, the placement of the tracks within the stereo field are adjusted and balanced. Audio mixing techniques and approaches vary widely and have a significant influence on the final product.

This is a glossary of jazz and popular music terms that are likely to be encountered in printed popular music songbooks, fake books and vocal scores, big band scores, jazz, and rock concert reviews, and album liner notes. This glossary includes terms for musical instruments, playing or singing techniques, amplifiers, effects units, sound reinforcement equipment, and recording gear and techniques which are widely used in jazz and popular music. Most of the terms are in English, but in some cases, terms from other languages are encountered.

Equalization, or simply EQ, in sound recording and reproduction is the process of adjusting the volume of different frequency bands within an audio signal. The circuit or equipment used to achieve this is called an equalizer.

A matrix mixer is an audio electronics device that routes multiple input audio signals to multiple outputs. It usually employs level controls such as potentiometers to determine how much of each input is going to each output, and it can incorporate simple on/off assignment buttons. The number of individual controls is at least the number of inputs multiplied by the number of outputs.

<span class="mw-page-title-main">Keyboard amplifier</span>

A keyboard amplifier is a powered electronic amplifier and loudspeaker in a wooden speaker cabinet used for the amplification of electronic keyboard instruments. Keyboard amplifiers are distinct from other types of amplification systems such as guitar amplifiers due to the particular challenges associated with making keyboards sound louder on stage; namely, to provide solid low-frequency sound reproduction for the deep basslines that keyboards can play and crisp high-frequency sound for the high-register notes. Another difference between keyboard amplifiers and guitar/bass amplifiers is that keyboard amps are usually designed with a relatively flat frequency response and low distortion. In contrast, many guitar and bass amp designers purposely make their amplifiers modify the frequency response, typically to "roll-off" very high frequencies, and most rock and blues guitar amps, and since the 1980s and 1990s, even many bass amps are designed to add distortion or overdrive to the instrument tone.

A professional audio store is a retail business that sells, and in many cases rents, sound reinforcement system equipment and PA system components used in music concerts, live shows, dance parties and speaking events. This equipment typically includes microphones, power amplifiers, electronic effects units, speaker enclosures, monitor speakers, subwoofers and audio consoles (mixers). Some professional audio stores also sell sound recording equipment, DJ equipment, lighting equipment used in nightclubs and concerts and video equipment used in events, such as video projectors and screens. Some professional audio stores rent "backline" equipment used in rock and pop shows, such as stage pianos and bass amplifiers. While professional audio stores typically focus on selling new merchandise, some stores also sell used equipment, which is often the equipment that the company has previously rented out for shows and events.

References

↑ "Mixing Principles". Leonard Audio Institute. Retrieved 2013-01-03.
↑ Tim Crosby (28 April 2008). "How Live Sound Engineering Works". HowStuffWorks . Retrieved 2013-03-03.
1 2 Joe Shambro. "Monitor Mixing 101" . Retrieved 2017-12-04.
↑ Clukey, Tim (January 2006). "Capturing Your Sound: A Guide to Live Recording". Music Educators Journal. 92 (3): 26–32. doi:10.2307/3401137. ISSN 0027-4321. JSTOR 3401137. S2CID 192140775.

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[1] "Mixing Principles". Leonard Audio Institute. Retrieved 2013-01-03.

[2] Tim Crosby (28 April 2008). "How Live Sound Engineering Works". HowStuffWorks . Retrieved 2013-03-03.

[Shambro-3] 1 2 Joe Shambro. "Monitor Mixing 101" . Retrieved 2017-12-04.

[4] Clukey, Tim (January 2006). "Capturing Your Sound: A Guide to Live Recording". Music Educators Journal. 92 (3): 26–32. doi:10.2307/3401137. ISSN 0027-4321. JSTOR 3401137. S2CID 192140775.

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