What a Mastering Engineer Needs From You
By Written by Peter McVeigh
What to send to mastering, how to prepare your mix and what to ask before you bounce it.
Mastering is the final step before release. A good mastering engineer can bring out the best in a mix, but they can't fix everything. How you prepare the files makes a real difference. It's also a simple way to avoid the awkward email saying your mix has clipped and they need it sent again.
Ask them first
Every mastering engineer has preferences. Ask what they want before you bounce, including the format, level and how they'd like to receive notes. Their instructions should come before any general advice, including what you read here.
Level and headroom
Many engineers ask for some headroom, meaning space below the maximum level. Leaving roughly 2 to 3 dB in the bounce is a common request, as it gives them room to work.
Don't try to make your mix as loud as a finished release. Loudness is part of the mastering stage. If your mix depends on a limiter, ask whether to send it both with and without.
Processing on the mix bus
Many engineers will ask you to remove any digital limiting from the master bus before you render. Some will also ask you to turn off bus compression. Others may be happy for you to leave your compression on if it's part of the sound. So ask, and consider sending both versions if there's any doubt. Above all, distortion in the source file can't be fixed later.
File format
Send a lossless WAV or AIFF, not an MP3. If your session was a 24-bit, 48 kHz or higher WAV, render the mix in the same format and label it that way. Don't convert it to a lower sample rate or bit depth first, as the mastering engineer can prepare the final delivery versions.
Check the mix itself
Listen to the whole bounce after exporting.
Listen out for clicks, pops and cut-off reverb tails.
Tame harsh "s" sounds, as these can get worse with mastering.
Check how it sounds on different systems: headphones, a car, a phone.
Leave a little silence before and after, so that nothing's cut off.
Meters can help, but your ears are the test.
What to include
A short note can help a lot. Include:
The artist and song names, spelled correctly.
The track order and any gaps or crossfades, for an EP or album.
A couple of reference tracks, and what you like about them.
Anything you're unsure of, or wish was different.
How the music will be released: digital, CD or vinyl.
ISRCs and other details, if they're creating files with embedded codes.
Your deadline.
Name files clearly, such as Artist_Song_mix_v3_48k_24bit.wav.
Should you send stems?
Some engineers offer stem mastering, where they get groups of tracks such as drums, bass and vocals. It gives more control, but it costs more and can blur the line with mixing. Ask if it's offered and whether it makes sense for your project. A strong stereo mix is usually what's expected.
Going for vinyl?
Vinyl has its own technical limits. Tell your mastering engineer early on, and ask about running times and whether a separate master would help. Let them talk to your pressing plant if needed.
Listening back
When the master comes back, listen on the systems you know. Compare it at a matched volume to your mix, as louder usually sounds better at first. Then ask whether it feels like your record. If something's wrong, give clear feedback, using timestamps. It's normal to have a discussion.
What to do next
Before your next bounce, send the mastering engineer one email asking what they want. Then work through the mastering section of our Delivery Checklist. It'll only take a few minutes.
Disclaimer
General information, not professional advice. Every session and client is different, so adapt this to your own situation.