Stem mastering and mixing are crucial techniques for music production. They have the goal to enhance the song and prepare it for distribution. But before delving into specifics, we need to dissect the terms and go back to basics.
The Stem in Stem Mastering and Mixing
First things first, stems—aka sub-mixes, subgroups, or busses—involve a group of audio sources mixed together. A stem can exist in mono, in stereo, or in multiple tracks for surround sound. When talking specifically about sound mixing for film, stems facilitate the final mix. In order to achieve the desired final mix, engineers join together dialogue, music, and sound effects as independent items. They call this process D-M-E. The whole process requires a certain order. For starters, engineers use the dialogue stem when creating and editing the trailer of a film. Then, they add music and effects to the sequence.
Stem Mastering
Now that the concept of stem is clear we can move on.
On the one hand, stem mastering is a technique that comes from stem mixing where engineers arrange the individual audio tracks and join them together. By doing this, users are able to have independent control and signal processing of each stem. They, too, are able to handle each element by itself.
Following this, stem mastering is the result of sub-mixes known as stems. A complete mix emerges when the engineer plays them all at the same time. Every time the stems are available, the user has total control over the mix. Stem mastering is common for complex productions or those than have too many restrictions. It is frequently expensive because it requires more time and special knowledge. This technique has become popular for it allows the user to make alterations to each of the elements involved in the mix before applying the final compression.
Stem Mixing
On the other hand, stem mixing is a technique that involves mixing audio material obtained from different groups of audio tracks and separating them before merging them into the final mix. A stem and a separation are quite similar. Some experts consider that stem manipulation and stem mastering are practically the same. Others, however, assert that stems are sub-mixes for separation mastering. Apparently, the distinction lies within how many separate channels of input are available for mixing, or at which phase they are towards reducing them to a final stereo mix. In stem mixing, users group audio tracks that have similar properties into tracks to allow an individual signal processing for each one.
A Final Bit of History
The stem technique originated around the same time as mixing boards did. From the very beginning, stems were capable of signing individual inputs to subgroup faders and to work with each stem mix independently. The stem technique is functional to control, process, and manipulate entire groups of instruments, as well as to streamline and simplify the mixing process. In order to achieve a variety of effects, engineers can route the stem-mix through its own signal processing chain. Within the music production universe, specialists use DAWs to digitally process and manipulate individual groups of audio tracks through plugin chains.
