Which model isolates the bass?

4stem splits into vocals, drums, bass and other, and lets you save the bass track as WAV. Use 6stem if you want guitar and piano on their own tracks too.

Is the extracted bass in tune with the original?

Yes — the separated audio is exported as-is, so pitch and timing match the original performance. Where the bass overlaps the kick in frequency you may hear some bleed; 6stem is worth trying in that case.

Does it work on synth bass and upright bass?

Both, yes. An upright decays differently from an electric bass but occupies the same role in the low end, so it separates. Synth bass is the less certain one: patches that extend broadband energy well above the fundamental sometimes get filed under other rather than bass.

The bass drops out in places.

Either the part rests there, or the kick coincided and the model assigned that moment to the drums. You can tell which by playing the drum track alongside: if the gaps line up with the kicks, it is the separation rather than the arrangement. Re-running on 6stem can change it.

How do I make the bassless version?

After separating, turn Solo off and mute only the bass. Choose “Export”, then “Mix”, to save a backing track with room for your bass. One separation gives you both the isolated bass and the mix without it.

Is it really free? Do I need to sign up?

It’s completely free with no account needed. Just open the page and pick a file.

Is the song I choose sent anywhere?

No. All separation happens entirely inside your browser.

Which file formats are supported?

MP3, WAV, M4A, AAC, FLAC and OGG, plus the audio track of video files.

Audio · processed on this device

Isolate the bassline.

Lift the bass out of the mix as its own track, so a line buried under the kick becomes easy to follow.

Free, no account
Stays on your device

About this process

Free in your browser · instant

One mix, separated into its individual parts

Bass extraction isolates the bassline — for transcribing the notes, building a minus-one to practise against, or replacing the low end in a remix.

Bass lives almost entirely in the low frequencies, so the split stands or falls on separating it from the kick drum. The two overlap, and a kick transient can carry through into the bass part. For following the notes this rarely matters, and the extracted bass transcribes cleanly.

Basslines are usually hard to transcribe because they are not really audible. Phone and laptop speakers reproduce almost nothing of the fundamental — roughly 40 to 80 Hz — so inside a mix the bass registers only as a vague weight carried by other instruments harmonics. Isolated, that confusion is gone, and the same speaker becomes enough to follow the movement.

When it is still hard to hear, take the extracted bass to the key and tempo tool and raise the key. It reaches +6 semitones, which is enough to move the line into a range small speakers actually produce. The intervals between notes do not change, so the shape of the part reads the same; subtract the semitones you added when you name the notes.

Highlights

Bass on its own track: The 4stem and 6stem models export bass independently of the rest of the mix.
Buried low end, audible: Separated from the kick and the rest, the pitch is followable even on laptop or phone speakers.
Bassless practice track: Mute the bass, export the mix, and you have a track to play your own part over.
No upload: Everything happens inside your browser.

Three simple steps

Open a file
Choose an MP3, WAV, M4A, FLAC or video with “Open file”, or drag it into the workbench.
Check settings and separate
Bass needs 4stem or better. 6stem returns the same bass part. On a phone, 4stem Fast is the one that runs. Check the settings selected for this task, then press “Separate”.
Listen and export
Use Solo and Mute to listen to the parts you need, then choose “Export” to save WAV or MP3.

Bass extractor — frequently asked questions

Which model isolates the bass?: 4stem splits into vocals, drums, bass and other, and lets you save the bass track as WAV. Use 6stem if you want guitar and piano on their own tracks too.
Is the extracted bass in tune with the original?: Yes — the separated audio is exported as-is, so pitch and timing match the original performance. Where the bass overlaps the kick in frequency you may hear some bleed; 6stem is worth trying in that case.
Does it work on synth bass and upright bass?: Both, yes. An upright decays differently from an electric bass but occupies the same role in the low end, so it separates. Synth bass is the less certain one: patches that extend broadband energy well above the fundamental sometimes get filed under other rather than bass.
The bass drops out in places.: Either the part rests there, or the kick coincided and the model assigned that moment to the drums. You can tell which by playing the drum track alongside: if the gaps line up with the kicks, it is the separation rather than the arrangement. Re-running on 6stem can change it.
How do I make the bassless version?: After separating, turn Solo off and mute only the bass. Choose “Export”, then “Mix”, to save a backing track with room for your bass. One separation gives you both the isolated bass and the mix without it.
Is it really free? Do I need to sign up?: It’s completely free with no account needed. Just open the page and pick a file.
Is the song I choose sent anywhere?: No. All separation happens entirely inside your browser.
Which file formats are supported?: MP3, WAV, M4A, AAC, FLAC and OGG, plus the audio track of video files.

Check the bass part in the demo

In the prepared separation of “Shining Star” by MaouDamashii / Koichi Morita, enable Solo on BASS to hear the bass line. Then turn Solo off and compare with DRUMS to distinguish bass notes from kick-drum hits.

On the audio separation page, choose “Open prepared demo”. This is previously separated audio, not a guarantee for your recording. Before transcribing, listen for kick-drum bleed and missing bass notes.

Go to the bass listening demo Original music and artist CC BY 4.0

Practice with the extracted audio

Save the extracted part, then slow its tempo to practice a phrase. Listen for other instruments left in the result or notes lost during separation.

Switch to “Pitch & tempo” in this workspace to use the audio with the current Solo and Mute settings. No file selection is needed. Export the separated parts as WAV or MP3 first if you want to keep them before further processing.

Change pitch and tempo

Guides for this task

Three ways stem separation makes learning a song by ear much easier
The bass is buried under the kick, the drum fill is gone before you can catch it. Three ways to get past the usual walls when your band is learning a cover.
Using stems for sampling and remixing
Lift a drum track to build on, or take a vocal phrase somewhere new. Three ways to put stem separation to work in a DAW, and three tricks for making the separation artefacts sit down.