Mixing & Mastering
What is it?
After all of the individual tracks of a song have been recorded, a mixing engineer steps in to work their magic. They begin by labeling and organizing the tracks into their similar groups. The song is often Normalized to ensure that the tracks are all at similar volume levels and no tracks peak. The engineer will then EQ each individual track to get the best tones out of the instruments and use high and low pass filters to eliminate any unneeded frequencies. The general goal of EQing is to make adjustments that allow all of the tracks to inhabit their own frequency areas. This allows the song to be clear and each instrument distinguishable. The same idea is also applied to panning the tracks to get a full, wide sound. Compression, reverb, delay, and other processors can be added to each track to get the desired tones for the instruments as well. Manipulating fades and effects throughout the songs with automation can help the engineer control the emotion of the song sonically. A lot of engineers will switch between headphones and the studio reference monitors to get a consistent sound for their mix on various sources. After hours of tweaking knobs and faders, and the song sounds as best as it possibly can: It’s time for the mastering engineer to step in.
The mastering engineer receives the stereo track along with some notes and reference songs from the engineer and/or the artists. This will help give the engineer an understanding of the sound that they are going for and so that the mix isn’t altered in areas that are intended to sound a particular way. Then, the finishing touches are added to the song by making slight adjustments primarily to the EQ, compression, limiting, and stereo enhancement. All of the songs mastered on an album are brought to similar levels so the album flows and is cohesive throughout. Spacing and fades are added to the beginning and endings of the songs. Usually the Red Book standard of 2 seconds is added in between songs unless otherwise specified. Audio mastering engineers often offer sequencing services for albums to put the songs in the desired order, label track names, as well as encode the tracks with ISRC. The mastering engineer’s primary goal is to provide a high fidelity, high clarity, professional sound that can be enjoyed by listeners on any source.
You could have a great mix without a great master, or vice versa, and still be unable to achieve a professional sound that can compete in today’s music world. The line between mixing and mastering should never be blurred. Attempting to combine these two steps into one will only hinder your music and prevent it from reaching its full potential.
Mastering is a complex process. Here are techniques involved:
This step fixes any hiccups in the original mix like unwanted clicks, pops or hisses. It also helps to fix small mistakes that stand out when un-mastered audio is amplified.
Stereo enhancement deals with the spatial balance (left to right) of your audio. Done right, stereo enhancement widens your mix, helping it sound bigger. It can also help tighten your center image by focusing the low-end.
EQing corrects any spectral imbalances and enhances elements that need to stand out. An ideal master is well-balanced and proportional. This means no specific frequency range is left sticking out. A balanced piece of audio will sound good on any playback system.
Compression corrects and enhances the dynamic range of your mix and keeps louder signals in check while bringing up quieter parts. This process gives the overall audio a better uniformity and feel. Compression helps glue together parts that might not be as cohesive as they could be.
The last process in the mastering chain is usually a special type of compressor called a limiter. Limiters set appropriate overall loudness and creates a peak ceiling. Limiting makes the track competitively loud without allowing any clipping that can lead to distortion.
BIT DEPTH REDUCTION & SAMPLE RATE CONVERSION
Sample rate conversion or dither is dependent on the final output medium. For example, if you are planning to release on CD you will have to convert to 44.1kHz 16 bit and therefore, you may have to convert and dither your file to get to the standard of format.
SEQUENCING & SPACING
Sequencing and spacing is one of the final steps in mastering. On an album or EP this process puts your audio in order. Spacing refers to how much silence (space gaps) you put between each track.