Plug-ins on the Master Output:
It’s best to mix without anything on the master output but if you are using plug-ins on the master output during mixing, then export two versions: One version with plug-ins enabled on the master output (except limiter) and one version without any plug-ins. Make sure clipping does not occur in any of the versions.
When we talk about clipping in this guide we are talking about digital clipping. Some people (including myself) find analog clipping very useful and can give your mix some interesting twist on individual channels. However digital clipping is never pleasant nor desirable and can cause serious problems down the line so it must be avoided at all times.
Having two mix versions gives us the choice in case you over-processed the mix. Make sure that your mix does not exceed the headroom when bypassing the plug-ins. If the master channel is clipping after bypassing the plug-ins, simply lower the master fader.
Your 24 bit mix should have its highest peak between -12 dBFS and -3 dBFS. (Decibels relative to Full Scale)
Headroom is the amount of dB before your mix is clipping and the overload indicator lights up on your master channel. When your mix is clipping then simply lower the master fader until the highest peak is within the recommended range. Sound quality will not be affected when lowering the fader.
While mixing the “volume” knob is your friend and digital clipping is your enemy. There is no reason to maximize the master level during mixdown.
On 24 bits, levels can go as low as -48 dBFS and still have full CD quality (16 bit). However, once you are clipping, distortion will occur, and it be impossible to restore to its original quality. We will make sure your song reaches its maximum loudness potential in the mastering process.
Tips for Mixing: Noise
Mute individual channels or groups when they are not active. This is especially important in the quiet parts where it will be most audible.
Phase and polarity
Check to see if recorded sounds are too much out of phase. Common problems are synthesizer sounds with too much anti-phase and applying a fake stereo spreader. Check your mix in mono playback. If sounds almost or entirely disappear fix it.
Most professional sequencers include a correlation meter to check for phase problems or you can use plug ins for this. +1 means in phase. -1 means out of phase.
Loud or unnecessary sub frequencies (below 40 Hz) in individual tracks can cause problems with the sound quality and the final level of the master. Make sure you low cut all tracks that do not contain meaningful sound in the sub frequencies (such as hi-hats, vocals etc). You can use a frequency analyzer for this.
An uneven vocal is difficult to fix in the mastering process. Sometimes two compressors with a low ratio is better than one compressor with a high ratio. Even with correct vocal compression you often still need to do volume automation. Turn individual passages or words up or down until everything is smooth and clearly audible. Listening at a low level while adjusting makes it easier to hear differences.
Export your mix at least one bar before it actually starts and include come extra bars at the end to ensure reverbs, delays, and instrument decays have faded out completely.
WAV or AIFF is preferred. MP3’s are not suitable for mastering.
Choose interleaved stereo and not split stereo when bouncing or exporting your mix.
If your sequencer does not give you a choice of stereo format then it is most likely using interleaved stereo. Interleaved stereo uses one single stereo file.
16 bit files are only used whenever it is not possible to get a 24 bit file of the same mix. All professional sequencers are able to export in 24 bit. 32 bit floating point is identical to that of the 24 bit fixed format, it just takes up more space, and is slower to data transfer.
44.1 kHz or higher.
Only export in higher than 44.1 kHz if your project is actually recorded and processed at that rate. If your project contains different sample rates then do not convert sample rates. We will do this for you.
Dithering and Noise Shaping:
Do not use noise shaping or colored dither, e.g. UV22 or POW-r when exporting your mix for mastering.
In very rare cases noise shaping can cause high frequency artifacts during the mastering process. You can use flat dither during the mixdown, referred to as TPDF. In all circumstances dithering and noise shaping on a 24 bit file has very little effect on the sound, so leave if off if you are uncertain. The final bit reduction to 16 bit (audio CD format) is performed by us as the last step of the mastering process.
Do not use any kind of normalizing on your mix.
Normalizing raises the signal level in an unnecessary fashion, and it will change the amount of headroom left in the mix. The final level of the mix will be optimized by us.
Realtime or Offline Bouncing:
In theory a realtime and offline bounce are identical. However, sometimes track automation and unsynchronized LFO’s are not identical due to small timing differences. If you decide to do an offline bounce then listen through the bounce before sending it to us.
Listen to Your Mixdown:
Sending a new mix will mean a new mastering so it’s important to listen to the exported file from the beginning to the end before sending. Make sure everything is playing correctly, that the beginning and end are intact, and that no artifacts or click sounds occur. It’s advised to do this a day after you have completed the mix, giving you a fresh ears and a fresh perspective.
Each mix has its own loudness potential. The final loudness of a master is not only determined by the mastering process but largely by the arrangement, production, sounds, recording and mix quality.
Various degrees of dynamic processing
A simple arrangement with few, but well-chosen sounds, has more loudness potential than a big arrangement with a lot going on simultaneously. We will determine when your song has reached its loudness potential and will adjust the master to it. Pushing the envelope beyond this limit will gradually deteriorate the sound quality, causing audible distortion and squashed dynamics.
We can have 3 degrees of dynamic processing.
- A dynamic master sounds coherent, pleasant, and has plenty of the original dynamics retained, but it will not compete with most commercial music in terms of loudness.
- A loud or pushed master is a compromise between a great sounding song and competitive loudness. It will sound good while being approximately as loud as most other pop music.
- A squashed master will sacrifice sound quality and dynamics in order to sound extremely
loud - the side effects being distortion and a complete lack of dynamics.