Audio mixing
Digital Mixing Console Sony DMX R-100 used in project studios Audio mixing is the process by which a multitude of sound sources are combined into one or more channels. channe ls. The source signals might be live or recorded a nd could be different musical instruments, instruments, vocals, orchestra sections, announcers or crowd noise. In the process, the source signals' level, frequency content, dynamics and panoramic position are commonly being manipulated and effects such as reverb might be added. This practical, aesthetic or otherwise creative treatment is done in order to produce an elevated mix that is more appealing to listeners.
Music production Audio mixing is done in studios as part of an album or single making. mak ing. The mixing stage follows the multitrack recording stage and the final mixes are normally submitted to a mastering engineer . The process is generally carried out by a mixing engineer (a mixer), though sometimes it is the musical producer who mixes the recorded material. A mixer working on a commercial release would normally spend 1-3 da ys mixing a single track, although times might vary greatly depending on budget, quality of the recordings and the complexity of the production.
Audio mixing on a personal a personal computer is computer is also gaining momentum. More and more independent artists are starting to use their personal computers for digital for digital recording and mixing their work. Audio editing on the computer is also easy and generally preferred.
Post-production During the post-production stage of a film or a television program, audio mixing takes place in a studio (or a theater) once the final cut is produced. Normally the engineer will mix 4 main elements: • • •
Speech (dialogue, ADR , Voice-Overs, etc.) Ambiance (or atmosphere) Sound FX
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Music
A 20 minute television program might be mixed in around 16 hours. A full-featured film might spend more than half a year in the mixing theater.
Public performance Sometimes audio mixing is done live by b y a sound engineer or recording engineer , for example at rock rock concerts concerts and other musical performances where a public a public address system (PA) (PA) is used. A big concert might involve two mixers, one located in the audience to mix the front of house (FOH) speakers heard by the audience, and the other located at the side of the stage, mixing for the monitor monitor speakers speakers positioned positioned directly in front of the performers so that they can hear one another.
Equipment Mixers A mixer, or mixing or mixing console, console, or mixing desk, or mixing board, or software mixer is the operational heart of the mixing process. Mixers offer a multitude of inpu ts, each is fed by a track from a multitrack recorder; mixers would no rmally have 2 main outputs (in the case of two-channel stereo mixing) or 8 (in the case of surround). Mixers offer three main functionalities: •
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Mixing - summing signals together, which is normally done by a dedicated summing amplifier or in the case of digital b y a simple algorithm. Routing - allows the routing of source signals to internal buses or e xternal processing units and effects. Processing - many mixer also offer on-board processors, like equalizers and compressors.
A mixer has numerous rotating controls ( potentiometers) potentiometers) and sliding controls (faders (faders which are also potentiometers also potentiometers)) that facilitate the manipulation of levels, the addition of effects such as reverb, and frequency content (equalization equalization)) of audio signals. On most consoles, all the controls that apply to a single channel of audio are arranged in a vertical column called a channel strip. strip . Larger and more complex consoles such as those used in film and television production can contain con tain hundreds of channel strips. Many consoles today, today, regardless of cost, have automation capabilities so the movement of their controls can be recorded, and then played back automatically, automatically, like a player a player piano. piano. A recent trend is to use a "control surface" connected con nected to a computer. This eliminates much of the electronics in a conventional console as the actual automation work is done digitally by the computer.
Simple mixing console
Outboard gear and plugins Outboard gear (analog) and software plugins (digital) can be inserted to the signal path in order to extend processing possibilities. Outboard gear and plugins fall into two main categories. •
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n ormally connected in series to the signal path, Processors - these are device are normally so the input signal is replaced with the processed signal (e.g. equalizers). Effects - while an effect can be considered c onsidered as any unit that affects the signal, the term is mostly used to describe units that are connected in parallel to the signal path and therefore they add to the existing sounds, but do not replace them. Examples would be reverbs and delays.
Common classes: •
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Processors : o Faders - used to attenuate or boost the level of signals. Pan pots - used to pan signal to the left or right and in surround also back o and front. o Equalizers - used to manipulate the frequency content of signals. Compressors - used to manipulate the dynamic content of signals. Among o many applications they can even the level fluctuations of a singer, or reshape dynamic envelopes of percussive instruments (e.g. adding attack to a snare). Gates - used mainly to attenuate low-level signals, for example, the kick o spill on a snare recording. Effects : Reverbs - used to simulate the boundary reflection created in a real room, o but that adding a sense of space to other wise 'dry' recordings. o Delays - most commonly used to add distinct echoes as a creative effect.
