Mixing console
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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.
Mixing consoles are used for applications including recording studios, public address systems, sound reinforcement systems, nightclubs, broadcasting, and post-production. A typical, simple application combines signals from microphones on stage into an amplifier that drives one set of loudspeakers for the audience. A DJ mixer may have only two channels, for mixing two record players. A coffeehouse's tiny stage might only have a six-channel mixer, enough for two singer-guitarists and a percussionist. A nightclub stage's mixer for rock music shows may have 24 channels for mixing the signals from a rhythm section, lead guitar and several vocalists. A mixing console in a professional recording studio may have as many as 96 channels.[1] Consoles used for live sound can go even higher, with some having up to 384 input channels.[2]
In practice, mixers do more than simply mix signals. They can provide
Terminology
A mixing console is also known as an audio mixer, audio console, mixing desk, sound mixer, soundboard, or simply as a board or mixer.
Structure
An analog mixing board is divided into functional sections. Some of the more important functional sections are subdivided into subsections.
Channel input strip
The channel input strips are usually a bank of identical
of the signal on each channel, controlling routing of the input signal to other functional sections, and adjusting the channel's contribution to the overall mix being produced.The types of inputs that can be plugged into a mixer depend on the intended purpose of the mixer. A mixer intended for a live venue or a recording studio typically has a range of input jacks, such as
Depending on the mixer, a channel may have buttons which enable the audio engineer to reroute the signal to a different output for monitoring purposes, turn on an
The channel strips are typically numbered so that the audio engineer can identify the different channels. For each channel input, a mixer provides one or more input jacks. On mid- to- large-sized live venue and sound recording consoles, these input jacks are numbered as well and consolidated in a
The input strip is usually separated into sections:
- Input jacks
- Microphone preamplifiers
- Equalization
- Dynamics processing (e.g. dynamic range compression, gating), if supported
- Routing, including direct outs, auxiliary-sends, panning control, and subgroup assignments
- Level-control faders (on small mixers, these may be rotary knobs to save space and cost)
On many consoles, these sections are color-coded for quick identification by the operator. Each signal (e.g., a singer's vocal mic, the signal from an electric bass amp's
Basic input controls
The first knob at the top of an input strip is typically a trim or gain control. The input/preamp conditions the signal from the external device and this controls the amount of amplification or attenuation that is applied to the input signal to bring it to a nominal level for processing. Due to the high gains involved (around +50 dB, for a microphone), this stage is where most noise and interference is picked up. Balanced inputs and connectors, such as XLR or phone connectors that have been specifically wired as balanced lines, reduce interference problems.
A microphone plugged directly into a
Audio engineers typically aim at achieving a good gain structure for each channel. To obtain a good gain structure, engineers usually raise the gain as high as they can before
A mixing console may provide insert points after the input gain stage. These provide send and return connections for external processors that only affect an individual channel's signal. Effects that operate on multiple channels connect to auxiliary sends (below).
Auxiliary send routing
The auxiliary send routes a split of the incoming signal to an auxiliary bus, which can then be routed to external devices. Auxiliary sends can either be pre-fader or post-fader, in that the level of a pre-fader send is set by the auxiliary send control, whereas post-fade sends depend on the position of the channel fader as well. Auxiliary sends can send the signal to an external processor such as a reverb, with the return signal routed through another channel or designated auxiliary return. Post-fader sends are normally used in this case. Pre-fade auxiliary sends can provide a monitor mix to musicians on stage (which they hear through
Most live radio broadcasting soundboards send audio through program channels. Most boards have 3-4 program channels, though some have more options. When a given channel button is selected, the audio will be sent to that device or transmitter. Program 1 is typically the on-air live feed, or what those listening to the broadcast will hear. Other program channels may feed one or more computers used for editing or sound playback. Another program channel may be used to send audio to the talent's headset if they are broadcasting from a remote area.
Channel equalization
Further channel controls affect the equalization of the signal by separately attenuating or boosting a range of
Cue system
The
Solo in place (SIP) is a related feature on advanced consoles. It typically is controlled by the cue button, but unlike cue, SIP affects the output mix; It mutes everything except the channel or channels being soloed. SIP is useful for setup of a mixing board and troubleshooting, in that it allows the operator to quickly mute everything but the signal being adjusted. For example, if an audio engineer is having problems with clipping on an input, they may use SIP to solely hear that channel, so that the problem can be diagnosed and addressed. SIP is potentially disastrous if engaged accidentally during a performance, as it will mute all the channels except one, so most consoles require the operator to take very deliberate actions to engage SIP.
Busses and submix
Each channel on a mixer has a volume control (
VCA groups
Some higher-end consoles use
Master output controls
The master control section is used to adjust the levels of the overall output of the mixer. The master control section on a large live venue or sound recording mixer typically has sub-group faders, master faders, master auxiliary mixing bus level controls and auxiliary return level controls. On most mixers, the master control is a fader. However, on some small mixers, rotary knobs are used instead to save space (and cost).
In a typical live sound mixing context, with a band playing at a venue, consisting of a rhythm section, solo instrumentalists and singers, the master control section allows the audio engineer to control the volume of the entire group with just one fader (for monaural mixers) or a pair of left and right faders (for stereo mixers).
Subgroup and main output fader controls are often found together on the right-hand side of the mixer or, on larger consoles, in a center section flanked by banks of input channels. Matrix routing is often contained in this master section, as are headphone and local loudspeaker monitoring controls. Talkback controls allow conversation with the artist through their
Metering
There are usually one or more VU or peak meters[a] to indicate the levels for each channel, for the master outputs and to indicate whether the console levels are clipping the signal. The sound engineer typically adjusts the gain of the input signals to get the strongest signal that can be obtained without causing clipping. Having the gain set as high as possible improves the signal-to-noise ratio. Most mixers have at least one additional output besides the main mix. These are either individual bus outputs or auxiliary outputs, used, for instance, to output a different mix to onstage monitors.
The meters may be above the input and master sections or they may be integrated into the input and master sections themselves. Meters may have needles or
As the human ear experiences audio level in a logarithmic fashion,[b] mixing console controls and displays are almost always labeled in decibels, a logarithmic measurement system. Since the decibel represents a relative measurement, and not a unit itself, the meters must be referenced to a nominal level. Most professional audio equipment is referenced to a nominal level of +4 dBu, while semi-professional and domestic equipment is usually referenced to a nominal level of −10 dBV.[5]
Hardware routing and patching
For convenience, some mixing consoles include inserts or a
Other features
Most, but not all, audio mixers can
- use monaural signals to produce simulated stereo sound through panning.
- provide phantom power required by condenser microphones.
Some mixers can
- add onboard external effect units (reverb, echo, delay). Mixers with onboard digital effects typically offer a wide range of these effects.
- create an audible oscillator. The test tone can be used to troubleshoot issues before the band arrives and determine if channels are functioning properly.
- read and write console automation.
- be interfaced with computers or other recording equipment.
- control or be controlled by a digital audio workstation via MIDI, USB or other communication interface.
- be powered by batteries.[c]
- provide amplifier power for external passive speakers
Mirroring
Some mixing consoles, particularly those designed for broadcast and live sound, include facilities for mirroring two consoles, making both consoles exact copies of each other with the same inputs and outputs, the same settings, and the same audio mix. There are two primary reasons for doing this; one, in the event of a hardware failure, a second redundant console is already in place and can be switched to (an important feature for live broadcasts); second, it allows the operators to set up two identical mix positions, one at front of house — where the audio will be mixed during a performance — and the other at some other location within the theater (e.g., with the broadcasting equipment); this way, if the acoustics at front of house are unfavorable, a mix can be programmed at an acoustically better position in the room, and the presets (on the faders and knobs) can be accessed from the front of house console during the performance.
Digital versus analog
Digital mixing console sales have increased dramatically since their introduction in the 1990s. Yamaha sold more than 1000 PM5D mixers by July, 2005,[6] and other manufacturers are seeing increasing sales of their digital products. Digital mixers are more versatile than analog ones and offer many new features, such as reconfiguration of all signal routing at the touch of a button. In addition, digital consoles often include processing capabilities such as compression, gating, reverb, automatic feedback suppression and delay. Some products are expandable via third-party audio plug-ins that add further reverb, compression, delay and tone-shaping tools. Several digital mixers include spectrograph and real-time analyzer functions. A few incorporate loudspeaker management tools such as crossover filtering and limiting. Digital signal processing can perform automatic mixing for some simple applications, such as courtrooms, conferences and panel discussions.
Latency
Digital mixers have an unavoidable amount of
Every
Within a digital mixer, there can be differing amounts of latency, depending on the routing and on how much DSP is in use. Assigning a signal to two parallel paths with significantly different processing on each path can result in comb filtering when recombined. Some digital mixers incorporate internal methods of latency correction so that such problems are avoided.
Ease of use
Analog consoles have a column of dedicated, physical knobs, buttons, and faders for each channel, which is logical and familiar to generations of audio engineers who have been trained on analog mixers. This takes more physical space but can accommodate rapid responses to changing performance conditions.
Most digital mixers use technology to reduce physical space requirements, entailing compromises in user interface such as a single shared channel adjustment area that is selectable for only one channel at a time. Additionally, most digital mixers have virtual pages or layers that change fader banks into separate controls for additional inputs or for adjusting equalization or aux send levels. This layering can be confusing for some operators. Many digital mixers allow internal reassignment of inputs so that convenient groupings of inputs appear near each other in the fader bank, a feature that can be disorienting for persons having to make a hardware patch change.
On the other hand, many digital mixers allow for extremely easy building of a mix from saved data. USB flash drives and other storage methods are employed to bring past performance data to a new venue in a highly portable manner. At the new venue, the traveling mix engineer simply plugs the collected data into the venue's digital mixer and quickly makes small adjustments to the local input and output patch layout, allowing for full show readiness in very short order. Some digital mixers allow offline editing of the mix, a feature that lets the traveling technician use a laptop to make anticipated changes to the show, shortening the time it takes to prepare the sound system for the artist.
Sound quality
Both digital and analog mixers rely on analog microphone preamplifiers, a high-gain circuit that increases the low signal level from a microphone to a level that is better matched to the console's internal operating level.
In a digital mixer, the microphone preamplifier is followed by an analog-to-digital converter. Ideally, this process is carefully engineered to deal gracefully with overloading and clipping while delivering an accurate digital stream. Overloading during further processing and mixing of digital streams can be avoided by using floating-point arithmetic. Intermediate processing in older systems using fixed-point arithmetic and final output in all digital systems must be controlled to avoid saturation.
Analog mixers, too, must deal gracefully with overloading and clipping at the microphone preamplifier and as well as avoiding overloading of mix buses. Noise is present at all stages of an analog mixer, though good gain stage management and turning unused channels down to zero minimizes its audibility. Digital circuitry is generally more resistant to outside interference from radio transmitters such as walkie-talkies and cell phones.
Many electronic design elements combine to affect perceived sound quality, making the global "analog mixer vs. digital mixer" question difficult to answer. Experienced live sound professionals agree that the selection and quality of the microphones and loudspeakers (with their innate higher potential for creating distortion) are a much greater source of coloration of sound than the choice of mixer.[citation needed] The mixing style and experience of the person mixing may be more important than the make and model of audio console. Analog and digital mixers both have been associated with high-quality concert performances and studio recordings.
Remote control
Since the option first appeared associated with analog mixing the 1990s as wired remote controls for certain digital processes such as monitor wedge equalization and parameter changes in outboard reverb devices, the concept has expanded until wired and wireless remote controls are being seen in relation to entire digital mixing platforms. It is possible to set up a sound system and mix via laptop, touchscreen or tablet. Computer networks can connect digital system elements for expanded monitoring and control, allowing the system technician to make adjustments to distant devices during the performance. The use of remote control technology can reduce the amount of venue space used for the front-of-house mixing console, and recover space for audience seating.
Software mixers
For recorded sound, the mixing process can be performed on screen, using computer software and associated input, output and recording hardware. The traditional large control surface of the mixing console is not necessarily utilized. In a software studio, there is either no physical mixer fader bank at all or there is a compact group of motorized faders designed to fit into a small space and connected to the computer. Many project studios use such a space-efficient solution, as the mixing room at other times can serve as the business office, media archive, etc. Software mixing is integrated as part of a digital audio workstation.
Applications
Public address systems in schools, hospitals and other institutions use a mixing console to set microphones to an appropriate level and can add in recorded sounds such as music into the mix. PA mixers usually have controls that help to minimize audio feedback.
Most rock and pop bands use a mixing console to combine musical instruments and vocals so that the mix can be amplified through a
Radio broadcasts use a mixing desk to select audio from different sources, such as CD players, telephones, remote feeds, prerecorded advertisements, and in-studio live bands. These consoles, often referred to as air-boards are apt to have many fewer controls than mixers designed for live or studio production mixing, dropping pan/balance, EQ, and multi-bus monitoring/aux feed knobs in favor of cue and output bus selectors, since, in a radio studio, nearly all sources are prerecorded or preadjusted.
Hip hop music DJs and Dub producers and engineers were early users of the mixing board as a musical instrument. In the 1970s, hip hop DJs developed a technique of adjusting the fader and crossfader controls of mixers at the same time as they manipulated records on turntables, creating unique rhythmic scratching effects.
Noise music musicians may create feedback loops within mixers, creating an instrument known as a no-input mixer. The tones generated from a no-input mixer are created by connecting an output of the mixer into an input channel and manipulating the pitch with the mixer's dials.
Gallery
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BBC Local Radio Mark III radio mixing desk
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Allen & Heath Mixing desk for live performance
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Mackie CR1604-VLZ mixing console in a home studio
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Solid State Logic SL9064J
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Focusrite Console 72 in 48 out with GML Fader Automation
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Harrison SeriesTEN
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Gecko Exodus Odyssey MXR 5204L
Notable manufacturers
- Alesis
- Allen & Heath
- Audient
- Automated Processes, Inc.
- AMS Neve
- Avid
- Behringer
- Cadac Electronics
- Calrec
- Crest Audio
- D&R
- DHD audio
- DiGiCo
- Electro-Voice
- Euphonix
- Fairlight
- Focusrite
- Harrison Audio Consoles
- Klotz Digital
- Lawo
- Logitek
- Mackie
- MCI
- Midas
- Peavey
- Phonic
- PreSonus
- QSC
- Rane
- Roland
- Shure
- Solid State Logic (SSL)
- Soundcraft
- Speck Electronics
- Stage Tec
- Studer
- Studiomaster
- TASCAM
- Telos Alliance
- Ward-Beck Systems
- Wheatstone
- Yamaha
- Yorkville
See also
- Aux-send
- Board mix
- Electronic mixer
- Mix automation
- Pan law
- Vision mixer – Video version of a mixing console
Notes
References
- ^ "96 Inputs and 22 Buses For Glorious Surround Sound". Yamaha. Retrieved 2016-12-20.
- ^ "Quantum852". DiGiCo. Retrieved 2024-04-20.
- ISBN 9780240521633.
- ^ Mixed Signals - Studying the basics of a Mixer's signal flow Archived 2008-09-30 at the Wayback Machine. Retrieved on 2008-08-20.
- ^ Robjohns, Hugh (October 2003). "Sound Advice > Q. Are all Decibels equal?". www.soundonsound.com. Retrieved 12 February 2020.
- ^ "Yamaha PM5D Sales Top 1,000 Units". Archived from the original on 2006-05-06.
- ^ Si Expression (PDF), retrieved 2017-10-30
- ^ Whirlwind. Opening Pandora's Box? The "L" word - latency and digital audio systems
- About.com. Retrieved October 18, 2012.
- ^ UrbanSteel (March 17, 2009). "Explanation about Matrix/ALD/IEM/Soundboard". U2start.com. Retrieved October 18, 2012.