An audio engineer is someone with experience and training in the production and manipulation of sound through mechanical (analog) or digital means. As a professional title, this person is sometimes designated as a sound engineer or recording engineer instead. A person with one of these titles is commonly listed in the credits of many commercial music recordings (as well as in other productions that include sound, such as movies).
Audio engineers are generally familiar with the design, installation, and/or operation of sound recording, sound reinforcement, or sound broadcasting equipment, including large and small format consoles. In the recording studio environment, the audio engineer records, edits, manipulates, mixes, and/or masters sound by technical means in order to realize an artist's or record producer's creative vision. While usually associated with music production, an audio engineer deals with sound for a wide range of applications, including post-production for video and film, live sound reinforcement, advertising, multimedia, and broadcasting. When referring to video games, an audio engineer may also be a computer programmer.
In larger productions, an audio engineer is responsible for the technical aspects of a sound recording or other audio production, and works together with a record producer or director, although the engineer's role may also be integrated with that of the producer. In smaller productions and studios the sound engineer and producer is often one and the same person.

Studio engineer could refer to either a sound engineer working in a studio together with a producer or to a producing sound engineer working in a studio.
Recording engineer is a person recording a record differentiating from a ...
Mixing engineer who performs mixes of already recorded materials. It is not uncommon for a commercial record to be recorded at one studio and later mixed by different engineers in other studios.
Game audio designer, engineer is a person who deals with sound aspects of game development.
Live sound engineer is a person dealing with live sound reinforcement. This usually includes planning and installation of speakers etc and soundmixing during the show. This may or may not include running the foldback sound.
Foldback or 'Monitor' engineer this refers to the person running foldback sound during a live event.
Systems Engineer is a person responsible for the design, setup and flying of modern PA systems which are often very complex.
Audio Post Engineer is a person who edits and mixes audio for film and television.

Live sound mixing is the art of combining and processing a number of audio signals together to create a "mix" that the audience or performers at a live show hear. There are two types of live sound mixing: Front of House (FOH) and Monitor mixing.
Whenever sound reinforcement is needed for a live performance of either music, theater, or spoken word, a sound system is set up to provide this reinforcement. This sound system generally comprises a number of microphones on the stage, a mixing board, a number of speakers, often a number of audio processing devices, and the cabling to connect all of these components. For smaller venues and sound systems, the performer(s) often do not need a live sound engineer to operate the system during their performance. But when the venue and complexity of the sound system reaches a certain size, at least one live sound engineer is needed to operate the system. A live sound engineer refers to a person that is experienced in the set up and operation of a sound reinforcement system.
For mid sized venues and sound systems, usually only one live sound engineer is needed to mix the sound. When only one engineer is present, both the Front of House mix and the Monitor mix are done by the one engineer with one mixing board at the Front of House position. For larger sound systems and venues, at least two engineers and a number of technicians are required to run the system. The two primary engineers are the Front of House engineer and the Monitor Engineer.

The Backliner or instrument Technician, is a person part of the sound crew responsible for the several instruments, like Drum, Bass Guitar, Guitar, Keyboards, ecc..
Usually instructed to change the strings, clean instruments, assist musicians and check instruments during the soundcheck and the concert or in studio.

In the music industry, a record producer (or music producer) has many roles, among them controlling the recording sessions, coaching and guiding the musicians, organizing and scheduling production budget and resources, and supervising the recording, mixing and mastering processes. This has been a major function of producers since the inception of sound recording, but in the later half of the 20th century producers also took on a wider entrepreneurial role. These activities comprise record production.

A recording studio is a facility for sound recording. Ideally, the space is specially designed by an acoustician to control audio reflections. Different types of studios record bands and artists, voiceovers and music for television shows, movies, cartoons, and commercials, and/or even record a full orchestra. The typical recording studio consists of a room called the "studio", where instrumentalists and vocalists perform; and the "control room", which houses the equipment for recording, routing and manipulating the sound. Often, there will be smaller rooms called "isolation booths" present to accommodate loud instruments such as drums or electric guitar, to keep these sounds from being audible to the microphones that are capturing the sounds from other instruments or vocalists.

Audio mixing is used for sound recording, audio editing, and sound systems to balance the relative volume, frequency, and dynamical content of a number of sound sources. Typically, these sound sources are the different musical instruments in a band or vocalists, the sections of an orchestra, announcers and journalists, crowd noises, and so on.
Sometimes audio mixing is done live by a sound engineer or recording engineer, for example at rock concerts and other musical performances where a public address system (PA) is used. A typical concert has two mixers, one located in the audience to mix the front of house speakers heard by the audience, and the other located at the side of the stage, mixing for the monitor speakers positioned directly in front of the performers so that they can hear one another.
Another example of live audio mixing is a DJ mixing two records together. Break beats are created by mixing between identical breaks. Often the end of one pre-recorded song is mixed into another so that the transition is seamless, which is done through beat-matching or beat-mixing, and possibly pitch control.
At other times, audio mixing is done in studios as part of multitrack recording in order to produce digital or analog audio recordings, or as part of an album, film, or television program. See: remix.
An audio mixing console, or mixing desk, or mixing board, has numerous rotating controls (potentiometers) and sliding controls (faders which are also potentiometers) that are used to manipulate the volume, the addition of effects such as reverb, and frequency content (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. Larger and more complex consoles such as those used in film and television production can contain hundreds of channel strips. Many consoles today, regardless of cost, have automation capabilities so the movement of their controls can be recorded, and then played back automatically, like a player piano. A recent trend is to use a "control surface" connected to a computer. This eliminates much of the electronics in a conventional console as the actual automation work is done digitally by the computer.
Audio mixing on a personal computer is also gaining momentum. More and more independent artists are starting to use their personal computers for digital recording and mixing their work. Audio editing on the computer is also easy and generally preferred.
A recent trend is mixing to 5.1, which is "Surround sound" audio. This requires 6 channels of audio: left, center, right, left rear, right rear, and low frequencies (subwoofer, or LFE). The demand for 5.1 in the audio and music domain was once small, but has recently increased dramatically, along with the introduction of 7.1 & 9.1 surround channel audio.

Mastering, a form of audio post-production, is the process of preparing and transferring recorded audio from a source containing the final mix to a data storage device (the master); the source from which all copies will be produced (via methods such as pressing, duplication or replication). The format of choice these days is digital masters, although analog masters, such as audio tapes, are still being used by the manufacturing industry and a few engineers who specialize in analog mastering.
The source material is processed using equalization, compression, limiting, noise reduction and other processes. Subsequently, it is rendered to a medium such as CD or DVD. This mastered source material is also put in the proper order at this stage. This is commonly called the assembly or track sequencing. More tasks such as editing, pre-gapping, leveling, fading in and out, noise reduction and other signal restoration and enhancement processes can be applied as part of the mastering stage.
The specific medium varies, depending on the intended release format of the final product. For digital audio releases, there is more than one possible master medium, chosen based on replication factory requirements or record label security concerns.
A mastering engineer may be required to take other steps, such as the creation of a PMCD (Pre-Mastered Compact Disc), where this cohesive material needs to be transferred to a master disc for mass replication. A good architecture of the PMCD is crucial for a successful transfer to a glass master that will generate stampers for reproduction.