What is Stem Mastering? Differences from Standard Mastering

The term «stem mastering» is widely misunderstood by amateur music producers. This article will explain stem mastering, its advantages and disadvantages, and when it may be better than more traditional mastering methods.

Before we get into the details of Stem Mastering, you should ask yourself, what is mastering? It is critical to understand the concept of mastering and a little bit of history before going any further.

What is Audio Mastering?

In the analog era, mastering meant transferring a recording from an analog tape to a master disc. Later, labels used this disc for duplication and distribution. Soon after, mastering engineers were also responsible for applying equalization during the transfer process to ensure optimal playback in vinyl jukeboxes. We have a whole other article explaining the History of Mastering if you want to learn more.

So what is mastering today, then? Mastering occurs after the mixing stage, and each track works together correctly, sitting at ideal frequencies. It’s the final step of the entire production process. Mastering deals with the equalization of the song as a whole, where specific frequencies of the overall mix might need to be emphasized or dialed back. It also Improves overall loudness using a multi-band compressor and a peak limiter. Additionally, dithering helps smooth fades and quiet areas when reducing bit-rate to the standard 16bit. 

Now that you know what Mastering is, I can explain the peculiarities of «stem mastering» and go through its use cases.

While in traditional mastering, we use a stereo track, a client can send several stereo tracks called «Stems» in Stem mastering. The Mastering engineer can use these to create a final master. This can be just an instrumental and a vocal track. But it can also be more complex, sending each group of instruments separately.

By sending multiple tracks, the Mastering engineer has more options and control over the final result. This is sometimes good if we mix the track ourselves and aren’t entirely happy with the result, as the engineer will have more room to work. But it can also be bad if our mix is already how we like it, and we only want the final push.

What is the difference between Mixing and Stem Mastering?

One can say that Stem Mastering is indeed mixing and not Mastering. In my opinion, it is neither or both. When mixing, you have all the individual raw tracks, and there’s a lot of work involved in processing every track separately so you can blend them. In Stem Mastering, this is already provided. Any processing you do is to change what the mixing engineer did.

After you mix the stems, you also have to Master the final mix. So stem mastering is also plain traditional mastering as well. Because you can’t master a track until you have the final stereo mix, this is, at least, until 5.1 is adopted in the music scene!

There’re several situations where Stem Mastering is the way to go. Most Mastering engineers will not be willing or are too poorly trained to work with Stems. Make sure your engineer is experienced in this technique and thinks it’s a good idea.

You should use Stem Mastering only if you, and more importantly your engineer, think that further improvements can be made using stems. This can be because the mix is not very good or lacks processing, or he would like to have more control over the final sound and add a creative touch.

In general, I would advise working on the mix before deciding to go for the Stem Mastering approach. Mixing is the stage where you should find the sound that you want, don’t wait until mastering to try and fix it. Expect mastering to improve a good mix, not to fix a bad one.

There are also things to consider when mastering using stems. You have to carefully group the instruments by type and balance level, panorama, and EQ in these groups. Because although the engineer can mix these groups to his liking, it will be harder for him to modify individual tracks inside a stem.

Conclusion

Hopefully, now you have a better understanding of Stem Mastering, and you know better to decide whether you want to use it or stick to traditional mastering. You can also learn more about Stem Mastering Techniques so you can apply them to your tracks.