Stems and Multitracks: What’s the Difference?
by Phillip Nichols, iZotope Contributor
January 5, 2017
Audio files are essential to modern audio production and are relied upon for successful collaboration, tracking, editing, mixing, remixing, and mastering. However, lack of proper file preparation or confusion about what files to use will net a lot of frustration and wasted time, money, and progress. Under the umbrella of audio files are two commonly used and confused kinds—multitracks and stems.
Sure, both are audio files, but what’s the difference?
Some people use “stems” and “multitracks” as interchangeable terms. Though they are related, they're not the same. Understanding the differences prevents mixups when it comes to requesting and sending files.
What are multitracks?
Multitracks are the recorded separate, individual elements of an audio production. Some may be mono, while others are stereo. They may have been recorded from microphones or direct inputs, programmed in a sequencer, or arranged in a sampler. In many cases, dynamics processors such as compressors and time-based effects such as delay and reverbare excluded to allow flexibility for the mixing engineer. The image below shows a folder of multitracks.
Multitracks
What are stems?
Stems are stereo recordings sourced from mixes of multiple individual tracks. For example, a drum stem will typically be a stereo audio file that sounds like all of the drum tracks mixed together. In most cases, additional processing such as equalization, compression, and time-based effects is included to ensure that the sound achieved by the mixing engineer is committed. The image below shows a folder of stems generated from a mix of the multitrack files displayed in the previous image.
Stems
As you can see, multitrack sessions typically have far more tracks than stem sessions. Whereas the track counts in multitrack sessions range from twenty to a couple hundred, stem sessions may contain only four to twenty tracks.
Multitrack sessions are created and expanded upon in the recording, editing, and mixing processes, while stem sessions are more commonly created after all the recording, editing, and mixing is finished—there are exceptions, of course.