From Audio Soup to Ear Candy!
Mastering is the final stage in the audio production process. When budget permits, mastering should always be handled by a professional mastering engineer who has the proper room, equipment, and pair of ears to evaluate the needs of your track.
Mastering Made Easy:
BEFORE YOU CAN MASTER A TRACK, you must have access to certain hardware and software tools. Nowadays many tracks are mastered exclusively with VST Plugin software. Whichever route you go, make sure to have the following tools:
- Compressor and Multiband Compressor
- Stereo Imager
Nowadays these tools can be had for very cheap, or even free.
For a great set of mastering tools, check out the Waves Plugin series, which has been used in the audio production industry since the 90’s.
Another excellent option is IZOTOPE’s Ozone Mastering Suite - an all-in-one package with a crisp and easy-to-understand layout.
Mastering Chain Order
Once you have your tools, you’ll want to make sure they’re set up in a practical order on your master bus.
Your master bus audio signal can be processed in any number of ways, but a standard chain order to follow is:
Equalizer -> Reverb -> Exciter/Saturator -> Compressors -> Stereo Imaging -> Limiter.
Now let’s talk a little bit more about each tool and what it’s used for.
There are two main uses for mastering stage EQ.
- Removing problem frequencies from the mix. For example, if you recorded a guitarist and the sound of him picking is interfering with the clarity of the hi hats, you’ll want to see if you can isolate the frequency content of that guitar picking and pull it out with a very thin but deep notch in the EQ.
- Giving an overall sheen to the final track. If you think back to songs from the 1980’s, you’ll notice how they all sort of sound alike. They all have a… 80’s sound. This is thanks to the sounds they use, the tinny radio speakers the songs played out of, and the mixing and mastering engineers of the day. In contrast, today’s pop hits are very bright sounding. You can achieve these different sounds by applying gentle reductions or boosts to different frequency ranges. Use wide Q values and changes of less than 2 dB to avoid drastically changing the character of your song.
Compressor and Multiband Compressor
The compressor is used for reducing the dynamics of your mix. In other words, if you have a very loud section and a very quiet section, and you want them to be more equal in volume, you can use a Compressor to average the two.
Multiband compression takes the above concept and applies it to distinct frequency ranges. Multiband compression is often used for mastering radio and television material so that certain elements of the music can be reduced in volume while dialogue is left untouched.
This tool allows you to offset the timing of the Left and Right speaker signals for designated frequency bands. This is often used on the higher frequency zones to turn a dull, mono mix into a very exciting and wide-sounding one.
But be careful – don’t use a stereo imager on frequencies below 200 Hz. Low frequency sounds tend to muddy up the mix when spread across the stereo field.
This is used to add harmonics to your track. Harmonics are frequencies that are mathematically related to the sounds playing (so they don’t sound out of place) and effectively make the music sound richer and fuller.
The limiter is last in the audio chain because its purpose is to make sure that none of the audio signal exceeds the threshold, and placing any tools after the limiter would risk disrupting that effect.
Many music producers have taken a liking to the limiter’s secondary effect: to make music louder. While that sounds wonderful (no pun intended), it does come at a price.
The way limiters make music louder is by reducing their dynamic range (as mentioned in the Compressor section) – quieter sections are made louder, and louder sections are made quieter.
What you end up with is a track that doesn’t change volume much, and one fundamental principle of music is that changes in volume are more interesting than unchanging volume.
Heavy limiting does have its uses, though - dance music for clubs, the radio (so that you can hear Lady Gaga over a droning engine), and TV use the technique to great effect.