Before submitting your songs for mastering

Consider removing any bus compression, EQ and other processing that has been applied to your whole mix, or send multiple versions.

Having the unprocessed (no bus processing) helps with mix analysis and mix diagnosis. If you have put compression, EQ or other processes on your mix, and you're comfortable with it, there's nothing wrong with leaving it on, however, consider sending us both a "processed" version of your mix along with a "raw" version. Sometimes it can be helpful to use a different treatment on the mix. By providing us with the different versions, we can provide you with more mastering options later.

Watch the peaks.

Please ensure that there are no 0dBFS peaks in your finished mix file. It is best to set the gain on your mix so that the highest peak no higher than
-3dBFS. We will bring the loudness back up as necessary, during the mastering process. 

Send mixes without the fade outs (if applicable).

Any dynamics processing applied during mastering will have an audible impact on the fades. For example, depending on how much processing is applied, any fade outs may appear to drop suddenly compared to a nice smooth transition. For this reason, it's best to finish the mastering of each mix, and then apply fades after that process has completed.

Send high bit-rate, high resolution, uncompressed files.

For example, 24-bit *.wav format, 96kHz (or whatever bit depth and frequency that you mixed the song in). Most compression algorithms such as MP3 are "lossy", meaning that in order to achieve that compression, pieces of the audio are actually removed. Even though it's not easy to hear what has been removed from the audio, from a mastering perspective you want all of the information available in the track because the equipment hears everything. You'll get the very best possible sounding masters if we can work directly with a raw, uncompressed source file. An alternative is to use the FLAC (Free Lossless Audio Codec) format, which can help you reduce file sizes by 30-50% without sacrificing audio quality. You can read more detail about this in our article "Maintaining sonic integrity before mastering".

Tips for great sounding mixes

Check your mixes for mono compatibility.

Even though we live in a Stereo/Surround world, mono is still alive and well. In fact it's common practice for DJs/live engineers to work in mono (Stereo is less important in a live venue due to the acoustics and the fact that the audience isn't staying in one listening position). When you switch your mix to mono, does the sound quality change dramatically (bass disappears or vocals are harder to hear)? If so, you may need to go back and review each of the tracks to find out what the source of the issue is (mic bleed, inverted polarity etc).

EQ your reverb returns.

A lot of reverb effects units (including plugins) enhance the bass in the reverb to make it sound more full. Some even have enhanced highs too. If you use reverb on several tracks, you can get a build up of reverbant "mud" from that excess bass, and in other cases harshness from the highs. You can avoid this by EQ'ing your reverb. Solo the return so that all you're hearing is the reverb, and then use the EQ to remove portions of the reverb that are not important to your mix. This will dramatically impact the clarity of your mixes!

Know your gear (including your software).

There is a lot of great gear on the market today, including software plugins, and many of these products do more than just one thing at a time. It's very important that you know exactly what your gear is doing to the audio - especially if using presets. Using the "Hit Mix" preset on a buss compressor may sound great at first, but it's important to understand exactly what it's doing. Is it squashing your dynamics? Is it adding unwanted noise or harmonics to the signal? Be cautious of plugins or other software that have really slick user interfaces/graphics. Most can be great tools if used correctly, but it's also very easy to trick yourself into thinking you're hearing quality audio because your brain likes what you see on the screen. Close your eyes, listen critically and let your ears be your guide.

More mix tips in Rob's article: Four mixing tips to help you achieve a great mix! - Mixing Articles

Tips for recording engineers

Watch your levels.

You've maybe heard this a lot but it's very important. Any distortion in a recorded track is next to impossible to remove. At best, you can mask it which is a compromise to an otherwise great sounding mix. Be conservative with recording levels.

Bit depth matters.

24-bit is significantly better than 16, and it is well worth the extra storage space and processing time. If you regularly work in 16-bit, 24-bit audio can make a real difference. High quality 24-bit audio offers a noticeable reduction in noise over standard (e.g. triangular) dithered 16-bit. You can also get away with lower recording levels during tracking which will further help to enhance the quality of your recordings and mixes.

For the highest fidelity and flexibility, use the cleanest and shortest recording path possible.

High quality linear  microphones, using the shortest possible cable lengths with good quality cable, clean connections running into an uncoloured preamp will ensure that you have the very best starting point to work from when you start mixing. There are many products out there that advertise having "character" or "warmth". Be very careful - sometimes it's great to have in certain situations but if it's the only preamp you have, then everything you record will be stamped with that character, which could soon become tiring! You can always add character later in the mix if you start with clean, uncoloured signal.