Mixing and mastering: differences and when to do it.

Mixing and mastering are different stages of music production. Mixing works on the relationship between the elements of a production, such as vocals, instruments, and effects. Mastering evaluates the result as a whole and prepares its presentation for the agreed-upon destination. Understanding this difference helps in requesting the appropriate service and providing feedback when something bothers you during the listening experience.

Both activities involve artistic and technical judgment. Neither needs to make the music fuller or louder out of obligation. The result must preserve the gesture of the work and function under the intended conditions. An intimate song and a piece of tension may require very different treatments.

What can the mix adjust?

In mixing, it's possible to change the balance between the available parts. The vocals can gain more prominence, the percussion can recede in a passage, and the instruments can acquire different spatial relationships. Processing and automation help to build continuity and contrast throughout the song.

These decisions depend on the material received. If the only available source is a stereo file, the freedom to alter a voice in isolation is different from that of a session with all parts arranged. Before hiring, explain the state of the files. An initial assessment can identify whether the request is for mixing, production review, or another type of work.

What does mastering evaluate?

Mastering focuses on overall balance, dynamics, continuity between tracks when relevant, and delivery conditions. Instead of reconstructing each instrument individually, it typically works on an already approved mix. There are approaches involving audio groups, but this needs to be agreed upon and doesn't automatically transform the process into a new mix.

THE iZotope's explanation of mixing and mastering. This highlights the difference between internal relationships and the overall finish. For the client, the practical consequence is that any specific need must be communicated before considering the mix complete.

Higher volume can confuse the comparison.

When comparing two versions, a slight difference in volume can make one seem more prominent. This doesn't prove that there's more definition or better balance. Maintain consistent playback conditions and, when possible, compare with a similar perceived volume. Avoid switching between devices or apps with different processing settings without noting the change.

Start by listening to the entire piece of music. Then, return to specific sections. If your attention is fixed on a small passage from the very first second, it can be difficult to perceive the overall trajectory. Also, take pauses: repeating the same fragment for too long alters your listening reference and can lead to contradictory requests.

How to write a workable return

Identify the version and the excerpt. Describe what you notice and what function you would like to preserve. “The voice becomes difficult to follow when the synthesizer kicks in during the second chorus” allows for the investigation of a concrete relationship. “Lack of professionalism” doesn't specify what needs to change and tends to shift the conversation towards general impressions.

A return can also acknowledge choices that should remain: the roughness of a voice, the silence before an entrance, or the weight of a percussion. Finishing doesn't mean erasing all irregularities. Some characteristics carry artistic intention and should be evaluated as part of it.

A didactic example of consolidated return.

In the version identified as revision 2, we want to preserve the contrast between verse and chorus. In the second vocal entry, two words are obscured by the high-pitched instrument. We ask that you evaluate this relationship without reducing the intensity of the entire chorus. The breathing noise at the end is intentional and should remain.

The example doesn't dictate which tool to use. It provides a listening problem, a priority, and an artistic constraint. The person responsible for mixing can then propose a solution within the available material.

In audiovisual media, listen also within the scene.

Music can function independently and still compete for space with the film. Therefore, your evaluation version needs to be heard alongside the narration, dialogue, and relevant effects. The final audiovisual mix brings these elements together and may require different music files than a version prepared for phonographic release.

A recurring need is to manage specific sets without rebuilding the entire production. In this case, the discussion about musical stems should happen before finalizing deliveries. It's also helpful to specify whether the music will remain available for standalone listening, as this option may require its own version.

Prepare the material before sending

Confirm the organization and format of the files with the professional. Do not apply conversions or additional processing out of habit. Send a reference of what has already been approved and explain if any effect is part of the language. When there are provisional tools, indicate this so that no one tries to finalize an element that will still be replaced.

• Identify the project, version, and person responsible for submitting it.
• Specify the destination for each final file.
• Gather the team's feedback into a coherent response.
• Record which elements and choices have been approved.
• Check the technical instructions before exporting.

The complete sequence of preparation and delivery is presented in the article on music production for audiovisual media. Defining these steps allows for more precise discussion of the final product and preserves what makes the music recognizable.

Prepare musical briefing

Source and further information

iZotope: What is the difference between mixing and mastering? The example chart and feedback are for educational purposes only and do not replace the evaluation of the files.