Free Stem Splitter: 6 Stems, No Sign-Up

Stems, multitracks and what a splitter returns

A stem splitter uses AI source separation to divide a finished stereo song into separate audio files, such as vocals, drums, bass and other instruments, that play back in sync and add up to the original mix. Each of those files is a stem.

In a recording studio, a stem is a submix. Every drum microphone is bounced into one drum file, every backing vocal into one vocal file. A multitrack is the layer below that, with the separate recording of each microphone and instrument, often dozens of tracks per song. Engineers deliver stems for mastering, film and live playback because a handful of files is easier to handle than a full session. The multitrack of a released song usually stays with the artist or label, which is why most musicians start from the finished mix.

A splitter works in the other direction. It starts from the stereo master and estimates the stems that could have produced it. The result looks like a studio stem set, but every stem is an estimate built from the same mixed signal, so each one can carry a little of the others.

MuseHub Stem Splitter returns six stems. They are separations of one mix, so they start at the same moment, run for the same length and sum back to the song when you play them together.

Two, four, five or six stems

Each separation model is trained to output a fixed set of stems. More stems give you finer control, and every extra split is one more boundary the model has to estimate. The table compares the layouts you will meet most often.

The vocal isolator and the vocal remover run the two-stem layout and each hand over one half. When a job only needs one part taken out, the drum remover returns the song without its drums as a single file. Choose the six-stem splitter when you want every part on its own.

Uses for each of the six stems

Stems for DJs

DJs mostly work with vocals and drums. The drum stem of one track under the acapella of another is the classic live blend, and a drums-only intro gives you a clean section to mix in over the end of the previous song. Build these edits at home before a set, so every transition is tested before you play it to a room.

Stems for players and students

Musicians use the stem player in reverse. Solo the bass or guitar while a line is hard to hear, then mute that stem and play the part yourself with the rest of the band. For transcription, a soloed stem gives your ears, and music transcription software, one instrument to follow without the others masking it.

Stems for producers

Producers use stems to rebalance and rebuild. Turn down a harsh guitar in an old demo, replace the drums with a new kit, or solo the kick and bass of a reference song to hear how its low end fits together before you balance your own. Stems also make sampling easier. A drum break cut from the drum stem loops without the vocal running through it, and a chord stab from the piano stem can be pitched and replayed across a sampler’s keys.

Bringing stems into a DAW

Most work with stems happens in a digital audio workstation (DAW). Every stem from one split starts at the same point and has the same length, so keeping them in sync comes down to importing them the same way and moving them together.

1. Download every stem you need. Each stem downloads as its own file, and results are kept for seven days. Save the files in one folder named after the song.
2. Switch off automatic stretching. Some DAWs warp imported audio to the project tempo. Turn that off for the import, or set the project tempo to the song’s tempo first, so no stem is stretched differently from the others.
3. Import all stems at the same position. Place every file at the start of the session, usually bar 1 or 0:00. Most DAWs, and free editors such as Audacity, can import several files at once onto separate tracks.
4. Group the tracks. Link or group the six tracks so a single drag or nudge moves all of them together.
5. Line the grid up with the song. Move the group until the first strong downbeat lands on a bar line. Loops and new parts then snap to the music.
6. Check the sum. Play all six stems at their original level and compare them with the source file. When the two sound the same, nothing has slipped.

When the song drifts off the grid

Songs recorded without a click track speed up and slow down slightly. Their stems stay aligned with each other, because they all follow the same drift, but they move against your DAW’s fixed grid. Either edit by ear and ignore the grid, or run your DAW’s tempo detection on the drum stem, which has the clearest hits, to build a tempo map that follows the band.

Cleaning bleed out of individual stems

A few simple moves in your DAW remove most of the residue a split leaves behind. Apply them per stem, and compare the result against the full song so you do not cut away part of the instrument itself.

• High-pass the upper stems. Vocals, guitar, piano and other instruments rarely need the lowest octave. A high-pass filter on each clears kick and bass residue that would otherwise muddy the low end of a remix.
• Low-pass the bass. Cymbals and vocal sibilance can leak into the bass stem as a faint hiss. A low-pass filter set above the bass’s highest notes removes it while keeping the pick or finger attack.
• Gate the vocals. Between phrases, the vocal stem often carries a quiet layer of the band. A noise gate or a few manual cuts silences those gaps.
• Leave the other stem as glue. When you rebalance a song, keep the other instruments stem in the mix, even at a low level. It holds the reverb and small sounds that make the stems feel like one recording.

Practicing slowly with stems

Stems turn a finished song into a practice track you can slow down. Load them into your DAW, loop the bars that give you trouble and lower the playback speed with time-stretching, which changes the tempo and leaves the pitch alone. Start at around 70% of the original speed, mute the stem for your own instrument and raise the tempo in small steps as the part settles under your fingers.

Stretch all stems by the same amount, or stretch the whole group at once, and they stay in sync. Our guide to changing speed, tempo and pitch in Audacity shows the same edit with free tools, including how to move a song into a key that suits your voice or a capoed guitar.

What limits the quality of a split

Separation quality varies more from stem to stem than from song to song. Knowing where the weak spots are helps you decide which stems to trust.

• Shared register. Piano, guitar and synths often play the same chords in the same octave. The model tells them apart by tone color, so a strummed acoustic guitar and a bright piano can trade notes between stems.
• Instruments without their own stem. Strings, brass, organ and synth pads go to the other stem. An organ or electric piano may be split between piano and other.
• Effects on the whole mix. Reverb and delay added to the full mix wrap every instrument in the same tail. That tail has to land somewhere, and pieces of it can end up in the wrong stem.
• Distortion. A distorted guitar spreads energy across the whole spectrum. It can mask the vocal and leak into several stems at once.

Bleed matters less in a finished track than it does in solo. Once the stems play together, or under new parts, small traces of other instruments are masked by the music around them. Judge a stem in the context where you plan to use it.

Splitters built into DAWs and DJ software

Some DAWs and DJ apps now include their own stem separation. Logic Pro, for example, has a built-in Stem Splitter. Built-in tools save a step when your software has one, and the stem sets they offer depend on the program and its version. A browser splitter returns ordinary audio files, so the same stems import into any DAW, sampler or DJ library on any computer.

Using stems from songs you don’t own

Splitting a song does not change who owns it. Every stem still belongs to the composition’s writers and publishers and to the owner of the recording, usually a label. Practice, study and transcription keep the stems on your own computer. Releasing a remix, a mashup or a track with a sampled stem usually needs permission from both sides. Official remix contests and licensed stem packs are the safer source for anything you plan to publish.