Basic Mastering Techniques
Basic mastering involves some form of equalization, loudness maximisation and other processing to gain a better quality sound from that achieved during the mixing stage.
Master for a Reason
Always master with purpose. Don't simply complete a process out of habit. Over processing can destroy a mix. Remember that mastering is not a matter of applying a blanket set of rules. Treat each song as unique and work to optimize its own set of qualities.
A song that is clipping/distorting can never be fixed in the mastering process.
To master effectively, suitable equipment and a proper listening environment is required. Factors to consider include:
- Monitor speakers, including proper positioning
- An appropriate monitoring output level
- A reference track to compare your material against
- Where possible, an acoustically treated space
- Tools for the job - Equalizer, compressor/limiter, exciter and anything else at your disposal
Adding equalization can mean the difference between a good song and great song.
Initially, use gentle, broad stroke adjustments to help subtly change the perception of dynamics and loudness of the track. The goal is to make the sound better without it sounding like it’s been equalized.
When equalizing, be sure to change the output of the gain to balance the loudness when ABing its effect on the audio. If you don’t, your ear’s bias towards the louder version which will impair your judgement on the EQ curve you have applied.
Once finished with the subtle broad stroke adjustments, move on to isolating any problem frequency by scanning the entire audio spectrum with a narrow band width and attenuate any problem frequencies. Never take this too far. It's more often than not a matter of balancing the solution against the compromise of applying such EQ adjustments.
Sometimes you have to accept that fixing something is beyond the scope of the mastering process; trying too hard to solve them can cause as many problems as you solve.
In order to make the track louder and give it more punch, it's important to apply loudness maximization (compression and limiting) to bring the overall average level up - the perceived volume of a song lies in its RMS (average) power and not its peak to peak power.
Not all music needs loudness maximization.
Prior to loudness maximization, a waveform is fairly uneven. After the wave looks more even, with the dynamic range reduced.
To achieve a louder sound, it is possible to add multi-band compression, which uses different amounts of compression across different frequency bands; usually the bass, mid-range and treble.
There are many plugins and software packages that allow you to maximize the loudness using a couple of simple controls. Usually there is a threshold and output ceiling. While the threshold is lowered the volume of the song will increase. The output ceiling is usually set to 0dB or just under. If the threshold position is lowered too much, distortion will become apparent. It's all about finding the sweet spot; a decent increase in loudness without distortion.
How loud to go is of much debate between both amateur and professional producers alike. Use your instincts, listen to other similar sounding songs and, whatever you do, don't squeeze the life out of it by over-processing your master.