How to Prepare a Mix for Mastering: A File Handoff Checklist

A mastering session can only work with the file it receives. If the export is clipped, mislabeled, or built around a format the engineer did not ask for, the first conversation may be about fixing the handoff rather than finishing the record.

There is no single premaster recipe that fits every engineer and online service. The reliable approach is to confirm the delivery requirements first, export from the session carefully, then listen to the actual file before sending it.

Start with the destination

Before changing project settings, ask the mastering engineer what they want. Confirm file format, sample rate, bit depth, headroom, channel layout, and whether they want one stereo mix or alternate versions. If the engineer provides a delivery sheet, follow it rather than a general online checklist.

The destination matters because engineers and services do not all use the same requirements. A specification for an automated upload service is not automatically the right target for a person mastering your record. Waves' own mix-preparation guide, for example, gives specific headroom guidance for Waves Online Mastering while also advising clients to check the preference of their chosen engineer.

If the answer is not available yet, keep the session at its native settings and avoid unnecessary conversions. A last-minute sample-rate change does not improve a mix by itself. It can add a processing step and make it harder to compare the export with the session.

Finish the mix before you print it

Listen through the whole song, including the first and last seconds. Check for clipped transients, unintended clicks, muted edits, abrupt fades, and reverb or delay tails that stop too early. These issues are easier to correct in the session than after delivery.

Compare the mix with a small number of references at matched playback level. A louder reference can seem better simply because it is louder. Use references to notice broad differences in tone, low-end balance, vocal placement, and stereo image, not to copy another record's sound.

If a problem appears in one instrument or vocal, correct it on that track when possible. Mastering works on the stereo mix as a whole. A click inside one vocal edit is not a useful problem to pass downstream if it can be repaired in the multitrack session.

Decide what stays on the mix bus

A limiter or loudness processor can change the dynamics and transient shape the mastering engineer receives. Ask whether the engineer wants a version with that processing removed, a version that preserves the sound you approved, or both. Do not silently remove processing that is an intentional part of the production.

Waves recommends removing master-bus processing used for a previous rough master when sending a mix to its online service. That is useful context, not a universal instruction to strip every mix-bus effect. Gentle compression, saturation, or equalization may be part of the sound; communicate what is active and why.

Do not apply final dithering as a routine export step unless the engineer specifically asks. Dithering is normally associated with reducing bit depth at the final delivery stage. Waves' guidance places it within mastering, so avoid doing it early and then asking for another reduction later.

Export a full-resolution file

Once the engineer's requirements are clear, choose an uncompressed WAV or AIFF unless a different format is requested. Export at the agreed bit depth and sample rate. If no one has specified a conversion, using the session's current sample rate avoids changing it just to match a number that may not apply to your project.

Do not send an MP3 as the only source for a mastering job. Lossy formats discard audio information. A compressed preview can be useful for listening or approval, but the engineer should receive the requested full-resolution source.

Check that the export is stereo if the project is a stereo mix. Confirm that the render begins and ends where intended, and that the file contains the complete song rather than a selected loop or truncated tail. If the engineer requests instrumental, clean, or alternate mixes, export each as a separate, clearly labeled file.

Listen to the export, not just the session

After rendering, open the exported file and listen from beginning to end. A session can sound correct while a bounce has the wrong start marker, a missing effect, a clipped ending, or an unexpected channel setting.

If the export is supposed to match the session, import it into the project and align it with the original. Listen for timing offsets, missing automation, or a sudden level change. This check is especially valuable when using offline rendering or a complicated routing setup.

Write down any details the engineer should know: approved version, alternate version, intentionally printed effects, desired sequence order, and any edit that remains under review. A concise note prevents guesswork without trying to direct every mastering decision.

Name and package the handoff

Use an unambiguous file name with the artist, song, version, and format. For example: ArtistName_SongTitle_Premaster_v03_24bit_48k.wav. If the engineer has a naming convention, use that instead. Avoid names such as final-final-new.wav that do not identify what changed.

Keep the package small and organized. Include the stereo premaster, requested alternates, a brief note, and any reference audio the engineer requested. Do not add unrelated rough bounces or old revisions without labeling them. If a file has an ISRC or sequence position that matters to the delivery, share it in the project notes rather than embedding guessed metadata.

Quick checklist before sending

• Confirm the mastering engineer's format, sample rate, bit depth, and level preferences.
• Export a full-resolution, uncompressed file unless a different format was requested.
• Avoid clipping and do not apply unrequested dithering or sample-rate conversion.
• Agree on whether master-bus limiting or other processing stays in the delivered mix.
• Check the start, end, stereo layout, and effect tails in the exported file.
• Compare against references at a similar listening level.
• Name the file with a clear song title and version number.
• Include the exact notes and alternate mixes the engineer requested.

The most useful premaster is not necessarily the quietest file or the one that follows a universal peak number. It is the clean, intentional mix that arrives in the format the mastering engineer can use. Ask before exporting, then verify what you actually send.

For a service-specific example, see Waves' guide to preparing a mix for mastering. Its online-service target should not be treated as a universal standard for every mastering engineer.