Mastering your final mix

Mastering is about the presentation of a mix.
The importance of full range, low distortion speakers and D to A converters for monitoring is critical. Mastering is mostly done by listening for and then fixing distractions. This can be tonality, dynamics, noises or distortion. My view is that mastering should not call attention to its self.

Bob Olhsson - Georgetown Masters

Just like playing a musical instrument, mastering is not impossible to do, and with a little practice you can do it yourself.

After a spate of recent loudness war victims (Death magnetic a good example) care should be taken not to master music too loudly only because other people do it that way. More info Here

Before we start:

  • Mastering is as much about the fresh set of ears as it is about all the rest. It is therefore recommended to use someone else to master your own work.
  • The word mastering originates from the process that was taken to prepare the final mix for duplication on the media of choice.
  • Disclaimer - the process described below is not the only method to master music.

In able to create a master that will translate well to most playback systems you have to make sure that you are able to hear everything that is going on in the final mix. You need:

  • Exceptional hearing: If you have gaps in your hearing, or limited range to your hearing, mastering is best done by someone that can hear the complete mix. Complete CDs have been recalled because a band, mixer and mastering engineer missed an annoying high pitched whine on the master...
  • A set of studio monitors, that are revealing enough to reveal problems, yet has a wide and flat frequency response to showcase to complete mix in the entire audible range. The quality and range of the speakers and the D/A converters leading to them are absolutely critical.
  • Large quiet room, treated for any unwanted frequency nodes.
  • Accurate dB SPL meter.
  • Calibrate your monitors to ensure the optimal playback of the mix. This will be outlined below
  • Time to get to know the monitors. Listen to a lot of well mastered reference material, and train your ears to the sound. This is the most time intensive step.
  • Playback system should be able to truthfully reproduce 24bit depth fidelity from the final mix supplied by the mixer.
  • Software as required

After getting all the hardware required, it is time to calibrate the system.

  • Start Jack and open Ardour.
  • Completely turn down the volume of each monitor and make sure they are off or muted
  • Load the 14dBFS-Pink wav file into ardour, and play out to the monitors. Be sure to leave the faders at 0dB positions on ardour and the playback hardware if applicable
  • Place the dB SPL meter to measure exactly in the spot where your head would be while seated at the mastering rig.
  • Unmute or switch on the first monitor and increase it's volume until the SPL meter reads 83dB. Mute again.
  • Complete the previous step on all monitors, one at a time

83dB SPL is the highest continuous sound pressure level, scientifically shown not to cause excessive fatigue and hearing loss while exposed for prolonged times. As an audio engineer, your hearing is quite important to you... better keep it protected.

Most of the applications needed are installed during your 64 Studio installation. Here is a list of the most important applications needed to create a master CD from a 24bit final mix:

  • Jack and qjackctl
  • Ardour
  • Jamin
  • jkmeter - compile from source : Download page
  • meterbridge
  • gcdmaster

Ear Training
After the hardware has been calibrated, you should train your ears.

  • Start jack, and using terminal: jkmeter -type k14 -V -C
  • Play back reference material, known to be good masters, preferably not from compressed media. and connect the player to jkmeter via jack as well as the output
  • During playback, make sure that the average levels stays around the 0dB level in jkmeter, on the louder sections of the music, if applicable. Adjust the software playback volume down if required.

This is required to be able to use your ears while mastering. Your ears are your most important asset, and during mastering, jkmeter should be used as a reference only.

After taking all of the above preparations, it is time to look at the mastering process itself. Before starting to master, the final mix should comply to the following to enable you to master it correctly:

  • it should be at the same sample rate as tracking took place in.
  • 24bit depth or higher preferred. Even if capture took place at 16bit, the mix has much more fidelity than 16bit because of summation effects.
  • No clipping allowed! To be sure specify that the mix should not have a peak higher than -1dB.
  • Supplied either non compressed, on in a lossless compression format

If all or most of these points are satisfied, continue to master the mix.

  • Start jack, ardour, jamin (jamin -p) , jkmeter (jkmeter -type k14 -V -C)
  • Import the mix to be mastered into ardour as a track, and connect its outputs to jamin from within ardour.
  • Create a new stereo bus, called mastering, and connect its inputs to jamin, and outputs to the ardour master bus.
  • Also connect the outputs from the "mastering" bus to jkmeter from within ardour. (connections from within ardour gets saved with the project)
  • In Jamin, make sure all compressor ratios (r) are at 1, and filters and other settings zeroed.

Now the fun begins. The section that follows is all about listening for, and removing or hiding distractions in the material.

  • listen to the track, specifically listening for frequency problems in the sonic field.
  • The first thing to correct is the stereo field. Listen to each of the three subsections below (using solo, and while playing, move the spacial correction slider slowly until the sound feels right, for each section. (Hard to explain)
  • Listen to the whole again, and identify areas in the frequency domain that needs enhancement or damping, and by using a combination of eq and compression fill in the frequency field. Take note that compression decreases dynamic range, and that compression ratios should be kept as low as possible to preserve the punch of the music.
  • Use the bypass button regularly, and try to compare it with comparable volume levels to prevent the placebo effect.
  • play with the settings available, see what they do, and how it influences the sound. Experiment a lot. It is your master.
  • Now, look at jkmeter while playing the track. The average loudness (loudest section) should hover around the 0dB mark in jkmeter. If it does not, use compression and boost to move the average up or down. Do not use the limiter too much, because the limiter has a distortion like effect on the audio, best left alone if possible.

After each track on an album is prepared, the comparative playback volume for each should be adjusted so as to place the tracks in the same relative space. This is needed to ensure coherence of the album as a whole.

Making the red book master CDR
When the master is completed, and you are happy with the sound, and the average levels in jkmeter did not move too far of base, you are ready to make the master disk.
Please follow the CD master burning how-to :