Picture this, you have just produced a piece of music. The client/label loves it and has asked you to send stems...and you think, "What the **** are stems?"
I've been there and I am here to help with this simple guide to explaining everything there is to know about stems, so you can confidently send your stems without worrying that you have sent the wrong thing.
What are Stems?
Stems are groups of similar sounding instruments and tracks exported together into one single audio file.
For example, there could be a string stem, guitar stem, drum stem, FX stem, vocal stem, brass stem, bass stem etc.
Sounds simple right? But, it opens up a barrage of questions about how to group the instruments, what form the audio file should be in, and how many stems are needed.
Why are stems needed?
Stems are needed for a few reasons; to mix and master the track, to allow for collaboration, for remixing and for more flexibility especially if your music is being used on TV or film.
I am asked to deliver stems in several different situations - when my music is being recorded by an orchestra, when my music is being mastered, and when a TV client wants to use my music on their production.
This basically means if someone, a client or producer, loves the track but they would prefer it not to have a certain element in it (vocals for example). Then they can take the vocal stem out and have the track as they want it.
Another aspect of creating stems is that it reduces the amount of files involved. Rather than dealing with 20+ audio files, using stems means that you might only be dealing with 4-12 audio files and this saves time and space on hard drives.
What are stems vs tracks?
A track is a single channel of audio or MIDI information. Individual elements within your piece of music.
For example, you could have a lead guitar track, rhythm guitar track, and acoustic guitar track. Each of those is an individual track.
You can then take those three tracks and group them together to form a stem; the guitar stem.
What are Stems vs Multitracks?
If you are being asked to supply a multitrack then you are expected to export and deliver all the individual channels as separate audio files. This allows for a lot more control of the mix/master.
When I write trailer music, I am often asked to deliver multitracks to the mastering engineer, as they like to have a lot more control of each individual sound. This is because they are mixing and mastering my music.
This means that when I am in my Logic Pro X session, I will export all the channels as individual audio files. This will often end up being between 30-70 audio files.
On the other hand, if I am asked to deliver stems it may only be between 4-12 audio files.
How Many Tracks are in a Stem?
The amount of tracks in a stem depends entirely on how many tracks you are working with. You may have a bass stem that only has one track. On the other hand, you may have a short string stem that has 12 tracks in it.
It doesn't really matter how many tracks are in a stem, as long as they are grouped together in a way that makes sense. Either by instrument type (strings, woodwinds, percussion, FX, etc.), articulation (short strings, long strings), or by importance (signature sound, lead vocals, etc.)
My rule of thumb is to group them into instrument type, but if there is a sound that might be more important or might be removed - vocals for example - then I will put them in their own stem. My signature sounds are often in their own stem.
Can you Master a Song Without Stems?
You can master a song without stems but it reduces flexibility by a great deal.
If you are mastering a song, the mastering plugins/hardware will be working on the whole track. This means that your mix has to be really well balanced.
For example, if my mix is too bass-heavy then when it comes to mastering it might come out sounding muddy and unclear.
This is why stems are important as they allow the mastering engineer to compensate for those mixing discrepancies and to "glue" the stems toghether more easily.
How Many Stems Should a Song Have?
There is no hard and fast rule for how many stems a song or piece of music should have. It depends largely on how complicated your music is. An orchestral piece will have a lot more stems than a solo piano piece for example.
Always bear this in mind when you are trying to figure out your stems. Group your similar sounding channels together and see how many stems you have.
You may need to combine some stems together if you have too many. In my experience, having more than 12 stems is surplus to requirements.
The mastering engineer or client might have a preferred grouping, so it is always worth asking.
Can you Mix a Beat Without Stems?
You can mix a beat without stems but it greatly reduces your flexibility and what you can do with the track.
When I started out pitching remixes for adevertising clients in 2007, I was often only ever given the final master in the form of a single audio file. I would then have to treat that as a stem in its own right and fill in the gaps.
When I have been given stems to mix a beat or make a remix it means that I can create a much more complete track and ultimately have a lot more fun and give it my own spin.
Should Stems be in Mono or Stereo
Stems should be delivered as stereo audio files. The sample rate depends on how it is being used. If it is being used for TV or film then they will be expected to be in 48kHz. Whereas if they are being used for mastering then 44.1kHz will do fine.
Should Stems be WAV or mp3?
I have never delivered stems in mp3 format, they have always been WAV/AIF files due to the higher quality and lack of compression.
Stems or Trackouts
Stems are sometimes referred to as "trackouts".
Trackouts are the same as stems - similar sounds grouped together into audio files.
I hope I have clarified what stems are and why they are important. If you are ever in doubt as to what to deliver then just remember,
- keep similar sounds together
- try not to exceed 12 stems
- Export them as stereo wav/aif files
- Ask if the engineer has any preference for delivery (sample rate etc.)