Many people inside and outside of music production misunderstand the difference between mixing and mastering. A lot of times, the two words are used interchangeably. Although both processes are related to music production, they are fundamentally very different and require very different hardware and technical know-how.

Do mixing engineers and mastering engineers perform the same job? No. The role of the mixing engineer is to gather all recorded tracks, but them together and form the structure and emotion of the song. The job of the mastering engineer is to polish and fine-tune the mix and prepare it for commercial or non-commercial release.

The processes of mixing and mastering are equally important, and both play a vital role in the final quality of a commercially, or otherwise, released song or album.

What Is Mixing? Mixing is the process of taking recorded audio tracks, putting them together, applying various processing and making a completed song.

What is Mastering? Mastering is the process of taking a completed mixed song, adding the finishing touches, and getting it ready for mass distribution.

Figure 1: Mixing Desk in Professional Studio

Summary of Mixing and Mastering Differences

	Mixing	Mastering
Process	Detailed. Visionary.	Broad. Polish.
Workspace	Working	Listening
Track Working Time	Long	Shorter
Tools	Many	Few (more expensive)
Headroom	20dB	5dB
Processing	By Instrument and song	Within album context
Decision Making	Artistic	Scientific

Table 1: The main Differences Between Mixing and Mastering

Mixing deals with a musician’ s vision for a song and is undoubtedly part of a creative process. Mixing deals with the details of a set of recorded audio tracks. In contrast, mastering deals more with the science of audio, and is the final polish to a finished piece of audio. Mastering uses broad brush strokes to present music or a song in its best light.

Workspace

Mixing Engineers and Mastering Engineers work in very different spaces. A Mixing Engineer’s studio is optimized to provide a very flat and honest reproduction of recorded and processed audio. Many mixing engineers work in the box and have little outboard gear.

On the other hand, a Mastering Engineer’s studio is kitted out with very expensive specialized loudspeakers, EQ processing, and state-of-the-art limiters. Mastering engineers also care very deeply about their A to D and D to A converters.

Project Time

A typical mix can take 8 to 10 hours to process and complete. A mix consists of several time-consuming preparing, processing, repairing, and finalizing steps. Depending on the number of recorded tracks, the quality of the tracks, and the complexity required to meet the musician’s vision, a mix can be a very time-consuming process.

The typical master is more likely to take around 30 to 60 minutes to complete, by a competent mastering engineer. In most cases, mastering is done to a stereo track pair which in comparison is a more straightforward process.

Tools

To mix a song these days, many mix engineers have a multitude of plug-ins available to them. The latest plug-ins come in every shape and form imaginable and are available with your favorite DAW at a fraction of the cost of their analog counterpart. The types of plug-in, and other tools, that are used to mix a song include:

• EQ
• Compression
• Saturation
• Stereo Width
• Reverb
• Chorus
• Delay
• Level
• Muting
• Panning
• Automation

On the other hand, mastering a track is usually done with far fewer tools. Mastering is generally carried out with high-end EQ, compression, stereo enhancement, saturation, limiting, and dither. The equipment used in mastering is usually, but not always, done with costly outboard processing units.

Headroom

When mixing a song, it’s always good to have enough headroom to maintain a decent amount of dynamic range. A mix on the K-20 metering system will have 20dBs of available headroom, and therefore allow the song to breathe, while maintaining a buffer to avoid digital distortion and clipping.

While mastering a song a mastering engineer will try to push up the average volume and keep as much dynamic range as possible without ruining the song. Headroom on a mastered track will typically be in the 5 to 6 dB range.

Emotion

The emotion of a song is something essential to understand while mixing and mastering. The mixing process is used to communicate feelings towards the audience and listeners. Techniques are employed by the mix engineer to convey emotion.

In mastering, however, the engineer generally does not alter the emotional content of the song. Instead, the engineer will enhance and maintain feelings and emotion created during the mixing phase.

Song Start and Fade Out

During the mixing process, little scrutiny is made to the silence at the start of the track or the fade out at the end of the track. The mix engineer’s job is simply to make the song sound as accomplished as possible.

It is the mastering engineer’s job however, to define the silence at the start of the track and how the track will fade out. This definition is usually done in conjunction with the song before, and the song after so that the album will have some continuity and coherence.

Commercial Loudness

Commercial loudness of tracks is something that the mastering engineer needs to consider. In many cases, where a mastering engineer is employed to master an album by a record company, the record company will dictate how loud they expect the album to be.

Loudness is set for songs that will be played on the radio, by CD, or by lossy compression formats such as MP3, AAC, and WMA.

Commercial Readiness

Part of the mastering process is to get the audio ready for commercial release. These days most of the music is released in digital format. Digital tracks can be assigned metadata about each song. Mastering engineers add data such as “song title,” “album title,” “artist,” “publisher,” “bit rate,” and “audio format.”

Processing

Processing on a mix is done track by track and often requires very detailed work. The levels of each instrument need to be set for verses and choruses in a song.

Processing for mastering is done with broad strokes.

EQ

When mixing individual tracks, EQ is applied according to each instrument. EQ is used to help instruments and vocals pop out when needed in a song. In extreme cases, EQ can be used to remove problematic frequencies surgically. EQ, in a mix, is also used, to counteract instrument masking and stop the audio from becoming too muddy.

EQ in mastering, on the other hand, is used with a broad Q and in lesser amounts. EQ is generally used to tweak the tonal characteristics of a song.

Compression

Due to the nature of recording instruments to tracks in a studio, the dynamic range seen in audio is usually quite high and requires to be controlled. Compression is used on the majority of tracks, or on group buses, within a mix session. Compressors are used to manage the dynamics of vocals, drums, bass, guitars, and other instruments.

Not only are compressors used to control dynamics but are often chosen to add character to instruments or tracks. A typical mix session may have more than 10 individual compressors. Compressors, for example, may be found on a snare drum, drum bus, parallel drum bus, and mix bus.

A typical mastering chain, on the other hand, would probably only have two compressors in it. One single band compressor would be used for very gentle taming of the dynamics. A second multiband compressor would be used to control various frequency ranges on a track separately. For example, a track may need heavy compression of the low end because of the limitations of the mixing environment, while little or no compression may be required for the mid-high range.

Saturation

Home studio owners do not always have access to preamps, or analog gear designed to add color and character to recorded material. In the digital realm, recordings of instruments and vocals are done in a very clean and sanitized way. In this case, the mix engineer typically prefers to add color using an arsenal of saturation plug-ins. The first insert on a track, in a typical mix, is often some kind of saturation plug-in, such as an analog tube or tape emulation.

Saturation used in mastering, on the other hand, is generally done with a dedicated 2 channel stereo processor used near the end of the mastering chain. Typical mastering saturation units include the WEISS DNA1 and the Dangerous Music Master.

Stereo Width

Apart from panning tracks in the mix, and adding stereo width to the mix bus, stereo width on an individual mix track is generally reserved for special effects, or to fix an unbalanced stereo recording.

In mastering, however, stereo width may be applied to the stereo pair to help separate the soundstage and present the music in its best light. This is especially true if the mix feels too narrow and is in need some additional stereo processing.

Automation

A mix engineer will often use automation on numerous tracks to aid with the leveling of instruments and vocals. The automation process is frequently carried out towards the end of a mix to put the final finishing touches on the track. Usually, the addition of mix automation results in a track having added character and emotion.

If the mix engineer has done a good job, the mastering engineer will not need to do any automation at all. In rare cases where the track demands it, mastering engineers may add automation to multiband compression, leveling or limiting.

Panning

To avoid masking of instruments on a multitracked recording, the mix engineer will use the pan pots to place instruments and vocals in the stereo image. Typically, instruments are panned hard left, hard right, or center, but can also be panned in between.

A track is always panned with the left track hard left, and the right track hard right. The mixing engineer does not pan any other way.

Limiting

In the mixing world, limiters often replace compressors as the tool to control dynamics. Limiters are also used to prevent single tracks or instrument group buses from clipping. And limiters are sometimes used as the last insert in the mix bus chain to increase volume for playback.

Limiting in the mastering chain is the final process carried out that can affect the tone and volume of a song. The limiting in mastering is used to bring the level up enough so that it can be commercially competitive and released in digital or analog form.

Dither

Unless the mix needs to be shared digitally before finalization, there is no need to use dither anywhere in a mix.

The same is not true for mastering. Dithering is a vital and essential mastering process. Dithering is always done last in the mastering chain and is necessary, so the audio is compatible for digital formats, or for printing to a CD.

Mixing and Mastering For Albums

Mixing is generally done with a single song in mind. Of course, the mixing engineer is mindful of the artist on the project, and the overall goal is to maximize the impact of all the recorded material. The mixing process is unquestionably concerned with the details of individual tracks, and bringing them all together in a cohesive, emotional, and balanced way.

Figure 2: Mixing and Mastering For Albums

Since the days of vinyl songs from a single artist or group are presented one after the other in album form. The mastering engineer’s job is to ensure that the album feels coherent, uniform, and consistent. Albums are made so that the listener can recognize the artist and understand the intended mood presented in the music.

The technicalities involved in mastering an album include level matching between songs, intro spaces, and fade-outs where appropriate.

Playback Systems

A home studio owner would be lucky to have several music systems with which to play back finished mixes. Most home studio owners have one pair of speakers and one pair of headphones. Of course, in professional studios, this is not the case, but their setup still does not compare professional mastering listening room.

Mastering audio helps to ensure that music can be played, and still sound good, on all playback systems. For example, mastered audio will sound good on a laptop, in the car, at the shopping mall, in an elevator, or on your state-of-the-art home hi-fi system.

Musical and Song Production Decisions

We mentioned earlier that mixing is considered part of the creative and visionary aspects of music production. A mix engineer is often chosen for his or her unique perspective on the music being made. In open collaborations, the mix engineer is given the freedom to develop the musician’s expression and vision. In turn, this means that, during the mixing process, the musical direction can be influenced, and artistic decisions will be made.

The mastering engineer, on the other hand, is not allowed such freedom and should only be inspired by the mix to create a perfect finished product. One advantage of separating mastering and mixing is that the mastering engineer brings a new pair of ears to the project and can, therefore, have a useful fresh perspective on the material.

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The Difference Between Mastering a Song and Maximising Your Mix

Since the explosion of affordable home studio recording and mixing, there are more mixing engineers and producers at home than ever before. Home produced songs are published in music forums and on song sharing sites everywhere. Due to the “budget” nature of these productions, many home studio owners do not send their mixes to professional mastering houses or engineers.

However, these enthusiastic home producers recognize that their mix is lacking volume when compared to commercial releases. As a result, the home producer will often apply limiting to increase the volume of their mix.

While this is the trend, and home producers are to be applauded for taking steps to compete with commercial releases, this is not mastering. This is merely maximizing the loudness of a mix.