Most of what goes wrong in a mastering session was decided before the session started.
This guide covers what I need from you, technically, creatively, and administratively, to do my best work on your project. It isn't a list of rules, everything here has a specific purpose and I'll try to explain my reasoning behind each guideline or comment. This post replaces an earlier AI-generated version on the same topic. This one is written from my own experience.
Your Mix Files
File Format
Send WAV or AIFF files. They're both high-quality lossless file formats. Either works fine; WAV is more common. Don't send MP3s.
For bit depth, 24-bit is the standard and what I prefer to work with. 32-bit float is also acceptable. Don't dither down to 16-bit before sending. That step happens at the end of the mastering process, not before it.
Match the sample rate of your recording session. If you recorded at 48kHz, export at 48kHz. Don't convert. I'd prefer to work with un-sample-rate-converted mixes if possible.
Stereo interleaved files are the most common format and work great. Separate mono left and right files are more old-school and also fine. Both work fine and it doesn't really matter, I just comment since I do get some questions occasionally about it. I don't typically work with stems unless there's a specific and compelling reason to. So unless we've talked about mastering from stems, send a stereo mix.
Headroom
Don't clip. That's the main thing. Red lights are bad.
Beyond that, give me something to work with. Mastering requires room to make decisions about level and dynamics. A mix that's pushing the ceiling before any mastering processing is applied leaves me with fewer options than one that has room to breathe. There's no magic number I need you to hit, but if I get a mix a -6LUFS I have way less options than a mix at -18LUFS.
Master Bus Processing
This is where I want to be specific, because it's where I see the most variation between engineers and one of the most common questions I get from engineers.
If you have a limiter on your master bus purely for volume control or clipping protection (to keep the mix from going over 0) remove it before you export (and of course make sure you're not clipping). Sending a limited mix means I'm starting from a decision I didn't make and can't undo.
Bus compression is a different conversation. For more experienced engineers, it's often integral to how the mix sounds and feels. If it's shaping the record, leave it in. If you've been playing your mix to a client or producer with a limiter engaged and that's the version they approved, send me both. Having both the version they heard, and the one without the limiter gives me more information on what the client expects. Knowing what was signed off on is useful context.
For engineers who are still developing their master bus approach, when in doubt, send me less rather than more. I can make dynamics decisions. I can't undo decisions that are already locked in. I almost universally recommend for these engineers not to mix with a master bus compressor. That's a whole other topic.
Heads and Tails
Leave them. Err on the side of more, not less.
The most common issue I run into isn't extra room at the start or end of a file, it's an attack clipped from the front of the first note, or a reverb tail that's been cut short. I'd much rather trim silence than work around audio that starts or ends abruptly.
If there's a count-off at the top of a track, leave it in. And let me know, especially if you want it included in the final song. That's a creative decision, and I need to know it was intentional. There are some exceptions, sometimes the count off has some reverb tail on it that overlaps the first note. In this case, you would have to cut that out in the mix. My main point here is give me some room in front and after the last bit of reverb tail, even extra after is good.
Labeling
Label everything clearly. I don't have a specific naming convention I need you to follow, as long as I can tell which file is which. If you're sending multiple versions (like an explicit mix, a clean edit, a radio version) make the difference obvious in the file name. Having this information makes the session run much more smoothly.
Communicating Intent
The technical side of a session is the easy part. The creative side is where things can go sideways if we're not on the same page before we start.
Reference Tracks
References are useful, but only when they're specific.
If there's a commercially released track in the same sonic territory as what you're going for, send it (or tell me where I can listen) and tell me what you're referencing specifically. Something like "I like the low end on this" is useful. Same as a comment like "I like how the vocals sit in the mix" is useful. Just noting a reference or sending a file without any context is less helpful, because I don't know what you're hearing in it. I'd probably ask questions and get the information, but sending that info can be more efficient. Even then, sometimes a conversation is better than written communication on this. A short conversation can go a long way in communicating these ideas when we can both be listening to and talking about these specific references.
That said, references aren't required. If you trust the work I do and don't have a specific target in mind, we don't need them. They're most valuable when a producer or client has a precise vision of what the finished master should feel and sound like.
Notes
A short note about the project is worth more than most people think. Even something like "we love the mixes and love your work, just do your thing" can make it really clear what you're expecting.
What is this for? Where will people hear it? What do you want them to feel? You don't need to write an essay, a sentence or two about the context can change how I approach the session. If you have something specific you're uncertain about in the mix, mention it. If there's something you're particularly proud of, mention that too. Both of those comments are always welcome.
What mastering can address and what it can't is a separate conversation, I've written about that before, but a note about intent is always worth including.
A Conversation
I always welcome conversations. I know a lot of people don't talk on the phone like we used to when I started mastering over 20 years ago. So much of my communication these days is over eMail or txt conversations I get surprised when my phone rings and it isn't a telemarketer. That being said, for first-time clients, or for projects with unusual requirements, a short call before the session is worth the time. I want to understand what you're going for before I start, not discover it midway through.
If something about your project is unconventional, a deliberately lo-fi aesthetic, an unusual sequence, a creative choice that might look like a problem if I don't know it's intentional, tell me. That information belongs at the beginning of the conversation, not after I've already made some mastering decisions or after you're reviewing version 1 masters. I'd always like to talk about that stuff before starting a session.
Project Information
Before I can deliver your masters, I need the project information that goes with them. I collect this through the Track Sequence Form. I have every client fill this information out. I've found it to be a very efficient way to gather information and gives the client flexibility to do that on their own time at their convenience.
The form covers your contact information, the services you're requesting, your intended release formats, album title, artist name, track listing and sequence, and metadata like ISRC and UPC if you have them. It also asks for production credits, producer, mixing engineer, recording engineer, studio. That information doesn't get encoded into your masters, but it helps me if anything comes up during the session and is worth having on file.
Release formats matter more than most clients realize. A streaming master, a CD master, a vinyl premaster, and an Apple Digital Masters delivery all involve different decisions made at different points in the process. Knowing your intended formats before we start, not after, means those decisions get made in the right order. If vinyl is part of your release plan, that conversation needs to happen early. I've written about vinyl mastering specifically before.
On ISRC and UPC: if you have these, include them in the form. If you don't yet, that's fine. I can encode them after you release and you can have archival masters with all that information together in one place. If possible, I think it's worth sorting out before your release date, not after. I have posts on both ISRC and UPC if you need background on what they are and how to get them.
Starting a Project
If you're ready to get started, or have questions before you commit to anything, the best first step is starting a conversation. You can reach me through the start a conversation form linked or just shoot me an email or give me a call or txt me or DM me on social media. I'm happy to talk through your project before you send anything.