How to Prepare Your Mixes for Mastering


Our engineers have compiled a set of common questions they get asked day in and day out about mastering. They’ve tried to provide some straight forward answers as well as pass on a few tips to make your next mastering session run a little smoother.

1. What file format do we need to bring to mastering?
Whether your mixes are being mastered for CD, on-line distribution, streaming or vinyl, 24-bit WAV files are the standard format to present at mastering. Sampling rates from 44.1kHz through to 96kHz are all perfectly acceptable. Please note that up-sampling your final mixes to a higher sampling rate will not yield any benefits whatsoever. In fact, it may result in a loss of audio quality.

2. Listen Carefully to Your Final Bounces
This may sound like an obvious point to make, however faulty bounces are the number one reason for hiccups and delays at the mastering stage. Don’t assume that your humble pc is going to output your 132 track mix perfectly every time.
Always listen to your final mixes from the beginning to the end before sending it to mastering. Make sure all tracks are playing correctly, and that there are no clicks, pops or mutes in the audio. This is especially important if there is heavy use of plug-ins on the mix.

3. Do I Normalize my mixes?
Don’t use any kind of normalizing on your mix-down. It’s simply not necessary, and some applications can actually degrade the audio with this process. A mastering engineer will never complain about too much headroom.

4. Do I need to limit or compress the stereo mix before mastering?
Compression on individual channels is perfectly fine, however avoid placing a limiter or ‘finalizer’ plug in on the stereo buss. Don’t be concerned if your mixes are not peaking at zero or sound quieter than commercial reference tracks you may be listening to. Your mastering engineer will take care of the final volume at the appropriate stage in your mastering session. Creative compression on the stereo buss is fine, just don’t use compression for the sake of raising the overall level of the track.

Even though we can never judge a mix based on how it looks, below is a typical example of what appears to be a healthy looking mix to present for mastering. Plenty of headroom for equalisation and other processing at the mastering stage.

The waveform below is an example of a mix with little, to no headroom. Not an ideal mix to be presenting the mastering engineer with. Mixes like this are so loud and have so little room to work with, it simply means that the mastering engineer cannot work as effectively on the mix.

Try and aim for a mix that has at least 5-6 dBs of headroom. An RMS (or average level) of -15RMS is a great volume to aim for in the final mix. Most level meters in modern recording software will have comprehensive meters to show you RMS levels, but if yours doesn’t, there are plenty of free metering plug-ins that are extremely useful. The ‘Flux Stereo Tool’ is an example of such a plug-in.

5. Do I need ‘ISRC’ codes on my master ?
Physical CDs

In a nutshell, ISRC codes help identify your music; like a digital barcode of sorts. If you’re pressing CDs and want to add ISRC codes on your CD master, then you need to bring the codes to the mastering session, so as the engineer can embed them onto the master disc. You need to apply for these codes via ARIA which may take anywhere from 2 to 5 days to arrive.
Not everybody wants them or needs the codes, but you can read the literature to help you make up your mind. There’s certainly no harm in having these codes on your master, and the following link will direct you to the ISRC handbook on the ARIA website: ISRC Codes
Digital Distribution
If you’re selling your music on-line, then you most certainly will need to obtain ISRC codes. These aren’t required at the mastering stage, however your digital store will ask for them when you upload your mastered wav files for distribution.

6. I’m selling my songs on-line as Mp3s. Can I bring Mp3s to mastering?
Even though this might seem logical, it’s an absolute ‘must’ to bring the full resolution wav file to mastering. Mp3s are simply not a professional nor desirable format to master from. It’s all about giving you the best possible sounding master.

7. Should I listen to my tunes outside my studio?
Definitely. Don’t fall into the trap of only referencing your mixes in your studio. Play your mixes on a variety of systems to get a feel for how they sound in real world environments. This will give you a good indication of any obvious problems that are present in the mix.

8. How far in advance do I need to book in at Crystal Mastering?
Generally, you need to allow 2 weeks to book in a session. If you need something mastered urgently, then we will try and arrange our schedule to make it happen for you.

9. Do I need to attend the mastering session?
Our mastering engineers are happy to work with or with-out artists attending. Approximately 90% of our work is done in unattended sessions, however we always welcome anyone who wants to sit in during the mastering. E-Mastering, our on-line service is available to everyone. Simply go to our website and use the ‘drop box’ on our e-mastering page – Crystal Mastering Dropbox . It’s as easy as clicking ‘browse’ & selecting your file. Alternatively if your mixes are already on line, simply email an invite to us at

1o. Do I really need to organise a listening session prior to my mastering booking?
We recommend our engineers hear your mixes prior to mastering if it’s the first time you’ve recorded an album, and unsure if the mastering process will be able to address certain issues. If you’re using an experienced recording engineer to produce your album, then chances are your mixes are in great shape. If you still feel like you want us to have a listen then we’d be happy to.

11. Tips for Vinyl Mastering
There are physical limits to what the head of a lathe can produce when cutting vinyl. Following are some general tips for mixes destined for vinyl;
a) Have the kick and bass centered in the mix. (not panned left and right).
b) Also avoid stereo panning any other ‘bass heavy’ instruments. Think bass, think mono.
c) Try to eliminate as much sibilance as possible on the vocal track (de-essing)
d) Avoid excessive amounts of sub bass frequencies (below 40Hz), as well as excessive top end (above 16kHz).
e) Avoid excessive buss compression & limiting.

Post Mastering

My song titles don’t show up on iTunes™. Why?
So you’ve rushed home after a rewarding day in the mastering studio, popped your reference CD into your laptop only to find that iTunes doesn’t recognise any of the songs! Ok… take a breath. This is normal. Don’t expect the reference CD from your mastering session to populate iTunes with all the song titles. It just doesn’t work this way; even with ‘CD-Text’ embedded. If you want iTunes, or similar media players to show song titles, you need to enter this metadata manually through your digital store who then submit the titles to a database known as ‘Gracenote’. It is this database that software like iTunes gets the track names, not from the CD itself. During this process of entering titles, you’ll also be prompted to enter other metadata such as Artist name, Album Title, ISRC code, Art work etc
You can read more about how to submit your CD to the Gracenote database here :
You can read more on how Gracenote works here :

Thanks for reading & best of luck with your recording,
From the staff at Crystal Mastering
CD & Vinyl Mastering Studios, Melbourne, Australia