Mixing or “mixdown” in music production is the merging of all analog or digitally processed individual sound tracks into one unit, the sum signal (“stem”). It is the penultimate process in the recording studio , followed only by mastering .
In the case of film, mixing in the broader sense means the mutual coordination of the audio tracks (dialogues, noises, music, sound effects and effect noises) and, in the narrower sense, the mixing of the many audio information to a master tape and the connection of the audio tracks with the master cassette.
The mixing phase has only existed in recording studios since the development of multi-track technology . The multi-track process began in January 1943 with two-track technology, which was already stereo-compatible. The engineers Helmut Kruger and Ludwig Heck began at that time in the Broadcasting Corporation in Berlin with the production of stereo recordings for archival purposes. Mixing in the current sense was not yet possible because both tracks were recorded synchronously on the same tape and recorded the same audio signals. It was only that of Ampex introduced in October 1955 three-track recorder ( "Selective Synchronous Recording", "Sel-Sync") allowed one overdub and enabled the first time the use of Abmischungstechniken.
The rock & roll successful authors Jerry Leiber and Mike Stoller broke new ground in the studio practice of pop music when they interfered in the recording process like never before and implemented their own compositions in studio work. The technical possibilities in the recording studio in 1955 were still quite modest, because it was only possible to combine different takes and create reverb effects. From 1956 on, Leiber / Stoller were the first to intervene massively in the recording process for design purposes and to use mixing techniques as an acoustic design element.
Phil Spector worked with three-track technology and developed through doubled or even tripled overdubbing ("double tracking"), a phase shift through the reverberation of an echo chamber and the wall of sound through over-orchestration or symphonic production . Spector called his mixing technique "little symphonies for young people" in a Wagnerian approach to rock & roll . The end result was highly condensed music productions intended for transistor radios .
Even stronger emphasis on Abmischungstechniken put the Beatles - music producer George Martin , who mainly recorded with four-track technology. He and the sound engineers Norman Smith and Geoff Emerick tried from 1967 to interpret the sound images of the Beatles and to preserve them on tape. John Lennon presented himself for the title Being for the Benefit of Mr. Kite! a fair or circus atmosphere, which is why a collage of steam organ recordings typical of the circus was built in.
In the advanced analog time, tape recorders (multi-track recorders) and tapes for the multi-track process were provided. From this time the term “soundtrack” has been saved in digital technology, although nowadays these are separate audio files . During the recording process ("recording session"), individual instruments and voices are recorded on individual sound tracks; the original sound unit is thereby broken down into its sound sources. A separate track is reserved for each instrument and separated from the rest of the sound sources. The number of tracks used depends on the number of instruments and the number of microphones used for recording. Recording on separate files or soundtracks has the advantage that the vocal or instrumental defects on a single track can be edited individually or only the affected track is re-recorded. A new recording with all those involved - as would be necessary with single-track technology - is thus saved.
Mixing phases in popular music
Once the last take has been recorded for all audio tracks , all selected audio tracks can be combined into one unit in a further phase. This is to achieve a natural-sounding, balanced and commercially usable overall sound. During mixing , the volumes of the individual sound tracks are matched to one another and these are distributed in the stereo panorama, right and left, or on a channel. In particular, the balance of the levels between rhythm section, background instruments and background vocals as well as lead instruments and vocals is determined. The mixing engineer can reproduce the music as it would sound at a concert (e.g. drums and singers in the middle, bass next to them and guitars on the sides). However, there are also mixes with complex sound collages where it is clear from the start that they can no longer be reproduced in live performances (e.g. parts of the Beatles LP Sgt. Pepper's Lonely Hearts Club Band ).
There is non-additive and additive sound processing. The non-additive is about muting individual sound tracks ( mute ) or adjusting the volume of the tracks ( level ). The additive sound processing takes place in the context of post-production (post-production). Here the individual sound tracks can be edited with sound effects . On the one hand, these ensure that each instrument can be perceived as such and, on the other hand, the piece of music is created as a unit. The equalizer creates more space for other sound tracks and works out the character of an instrument more. Reverberation or compression ensure that the song matures into a unit. The mixing process ends in the fact that the piece of music is combined on a single stereo track (with one channel on the left and one on the right). The result is a fully synchronized music track that serves as the basis for the master tape. Overall, when mixing, the musical balance is created and the sound design is completed.
The sound engineer (or "mixing engineer") uses a mixing desk (console) that provides separate control options and effects for each audio track. The mixing by the sound engineer is of the greatest importance in pop and rock music with regard to the sound quality as an independent aesthetic design tool.
For example, chief engineer Lawrence Thomas Horn at Motown Records did the final mixing. The result was presented to label owner Berry Gordy on Friday as part of the “Quality Control” and examined before the mastering took place. An essential criterion was the filtering of the sound so that residual tones were created through the left spectrum of the overtones .
In film production, the term “mix” or “re-recording” is used to describe the process in which a master tape is made from the various audio information that came about during the making of a film. For this, in particular atmosphere, original sound, synchronization or sound effects are brought together. The “premix” is the combination of several tracks of the same sound type (noise, language, music), while the “final mix” is the combination of the pre-mixed tracks with the music tracks.
In a narrower sense, mixing is already part of post-production (post-processing). In music production, post-production includes all processes that lie between the end of the music recording and the delivery of the finished master tape. The audio mastering that follows the mixing is also part of the post-processing.
In the phase structure of a film production, post-production includes all processes that lie between the end of the shooting and the delivery of the finished film. The film and sound material created during the shooting is arranged and cut, image and sound processed, special effects inserted, the colors corrected, the sound applied and the copying work coordinated, monitored and controlled.
- Georg Berhausen-Land: The art of mixing on the PC . Wizoobooks, 2006, ISBN 978-3-934903-54-8 .
- Florian Gypser, Holger Steinbrink: Mixing Practice Guide . audio workshop, 2007.
- Florian Gypser: Mixing . audio workshop, 2007.
- Bobby Owsinski: Mix like the pros . 2nd Edition. GC Carstensen Verlag, 2013, ISBN 978-3-910098-44-2 .
- Mixing & Mixing Tutorial on delamar Many practical examples on the subject of mixing
- Mixing tips and tutorials on mixing and mastering Link collection on the topics of mixing and mastering
- Cream of Audio , Stereophonie bei der RRG , August 13, 2010
- Mix Online: Ampex Sel-Sync 1955: When the Roots of Multitrack Took Hold ( Memento from January 31, 2010 in the Internet Archive )
- Virgil Moorefield, The Producer as Composer , 2010, p. 7
- Virgil Moorefield, The Producer as Composer , 2010, p. 8
- Richard Williams, Phil Spector: Out of His Head, 2003, Chapter 5: Little Symphonies for the Kids , pp. 53 ff.
- Mark Lewisohn, The Beatles Recording Sessions , 1988, p. 99
- Wieland Ziegenrücker / Peter Wicke, Sachlexikon Popmusik , 1987, p. 9
- Peter Wicke, Rock and Pop: From Elvis Presley to Lady Gaga , 2011, p. 81
- The lexicon of film terms at the University of Kiel, article mixture, sound mixer