Stems01
Stem separation
Vocals, drums, bass, guitar, piano and everything else as separate tracks, each with a confidence score. Solo the part you are learning, mute the rest, download any of them.
Learn any song. Learn any instrument.
PlayByPart is two tools for the same goal: Aura Stem takes a recording or a sheet apart so you can study it, and Hone teaches you to play it, listening while you practise.
Aura Stem
Separate any song into vocals, drums, bass, guitar and piano; follow the chords; slow down and change key; lead sheet and full score; play any music sheet; accompaniment for singing.
Web app · pay per file · open the studio →
Hone
Graded courses for piano, violin, flute, guitar, bass, ukulele, voice and drums; the sheet on screen, a demonstration with finger markers, and every note you play ticked or crossed through a microphone, a connected instrument or a MIDI keyboard.
Windows app · one-time licence · learn more →
No subscriptions · your music stays yours · PlayByPart
Aura Stem runs in the browser · Hone runs on your computer, offline · Free professional metronome in both · Public-domain repertoire · Honest about accuracy
01 / Aura StemReal screenshot — captured in PlayByPart
Hear every part. Read every chord.
A 4-minute song after separation: the vocal, drums, bass and guitar each on their own track, key and tempo detected, the chord timeline following the music, and speed and key controls that respond while you listen.
02 / What it doesEverything in one upload
The control that a play button cannot give you.
Listening on repeat only gets you so far. Pull the song apart, slow the hard bar down, put it in your key, and read what the harmony is actually doing.
Harmony02
Live chords, key and tempo
The current and next chord follow the song in real time, with a timeline of the whole piece. Key, BPM and time signature are detected, and anything uncertain is clearly marked.
Practice03
Slow down, change key
Speed from 0.5× to 1.5× without changing pitch; transpose ±12 semitones without changing speed. Instantly, per part or all together, while you listen. The chord names follow.
Notation04
Lead sheet and full score
Engraved PDF notation: the melody with chord symbols on one staff, or a conductor's score with every part. Chords as CSV and JSON, notes as MIDI, the transcription as MusicXML.
Playback05
Play any music sheet
Upload MusicXML, MIDI or a scan of printed music and hear it played with the instruments you pick, from choir and piano to strings, guitar and flute. Download as WAV or MP3.
Accompaniment06
Accompaniment for your singing
Record a melody, choose a style, and get chords or a tanpura-and-tala backing that follows your tempo and key. Western and Indian classical styles, with the instruments you choose.
03 / Who it's forBy ear, by eye, by playing along
Made for the way musicians actually learn.
Singers
A backing track in your key
Mute the vocal to sing with the band, or solo it to hear every phrase. Transpose to your range; read the melody as a lead sheet.
Guitar & keys
Chords as they go by
The current and next chord shown ahead of the beat. Slow a solo down without changing pitch and loop the bar you are learning.
Choirs & worship teams
One sheet for everyone
Give every member the same lead sheet and backing mix. Transpose to the congregation's range in one click.
Teachers
Materials in minutes
Turn a recording into a full score, chords as CSV and notes as MIDI. Credit packs for a whole class, no accounts to manage.
Carnatic & Hindustani
Practise with a sruti and tala
Detects the Sa and tempo of a sung melody and adds tanpura, violin or harmonium with the tala, so you can practise with accompaniment.
Home producers
Clean stems to build on
WAV stems, mixes of the parts you pick, and a transcription to start an arrangement from.
04 / How it worksMinutes, not days
From a recording to a practice session.
01Upload
MP3, WAV, FLAC, M4A or AAC, up to 2 hours. Confirm you own the music or have permission to use it. You see the exact price first.
02We take it apart
Separation and analysis take a few minutes and you watch every step. Your secret key lets you close the page and come back.
03Practise
Solo parts, follow the chords, slow it down, change the key. Download the lead sheet for the stand.
04Keep what you need
Stems, mixes, lead sheet, full score, chords and MIDI. Files are deleted from our server an hour later.
05 / PricingNo account · pay per file
One credit, one file. Nothing recurring.
A credit covers one file up to 15 minutes: a song separation, a music-sheet playback or an accompaniment. Longer recordings use one credit per started 15 minutes (2 hours = 8 credits).
Pack
$10
5 credits · $2 each · save 33%
- Credits never expire
- Songs, sheets or accompaniments
- A handful of songs
Pack
$15
10 credits · $1.50 each · save 50%
- Credits never expire
- Regular practice
- Use the same key on any device
Best valuePack
$20
20 credits · $1 each · save 67%
- Opens the loyalty week: for 7 days, extra credits cost $1 each (minimum 5)
- Teachers, choirs and bands
- Credits never expire
Your secret key is your wallet. When you buy credits you get a secret key, or add credits to the key you already have. Credits, downloads and the loyalty week are all tracked by that key: no account, no password, no email required. Keep it somewhere safe and keep it private; if you lose it, we cannot recover your credits. The loyalty week starts when the 20-credit pack is bought and closes 7 days later; buying the 20-credit pack again opens a new week.
06 / Straight talkWhat AI can and cannot do
Honest about accuracy.
A
Separation is very good, not perfect
Vocals, drums and bass separate best; guitar and piano can bleed into each other. Every stem shows a confidence score, and you hear the result before you download anything.
B
Notation is a strong first draft
The lead sheet is readable and useful. It is an automatic transcription: expect a few wrong notes or rhythms, especially in ornamented singing. Uncertain chords carry a ?.
C
Scans need clean print
Printed music scans well; handwritten manuscripts usually cannot be read. MusicXML and MIDI from notation software play back exactly.
D
Your rights, your music
Use it for recordings you own or have permission to study. We never publish, share or keep your files beyond the retention period. Copyright policy.
07 / ComparedWhy PlayByPart
| PlayByPart | Other stem apps | Hiring a transcriber | |
|---|---|---|---|
| Price | $3 per file, $1 in packs; you pay only for files you process | Recurring plans, paid whether you use them or not | Tens of dollars per song |
| Stems + live chords + notation + sheet playback in one place | Yes | Usually stems and chords only | Notation only |
| Account required | No, a secret key | Yes | Email back and forth |
| Turnaround | Minutes | Minutes | Days |
| Indian classical accompaniment | Tanpura, tala, melody-following violin or harmonium | No | No |
| Files deleted automatically | One hour after results | Varies | Varies |
08 / Questionssupport@riverthought.com
Frequently asked.
Can I upload any song?
Only music you own or have permission to process: your own recordings, music you bought for personal study, or public-domain works. Your results are for your own practice; we never publish or share them. See our copyright policy.
What is the secret key?
Your secret key (PBP-…) is how we know you: it holds your credits, lets you come back for your files, and tracks the loyalty week. There is no account to create and nothing to remember except the key. Store it in your password manager or notes. Anyone with the key can use your credits and open your files, so never share it; if you lose it, your credits cannot be recovered.
How accurate is the separation?
Very usable for practice; not studio-perfect. Vocals, drums and bass separate best; guitar and piano can bleed into each other. Every stem card shows a confidence score.
Is the sheet music ready to perform from?
The lead sheet is readable and useful for singers and guitarists. It is an automatic transcription: expect some wrong notes and rhythms, especially in ornamented singing. Treat it as a strong first draft.
What formats of music sheet can I upload for playback?
MusicXML (.musicxml, .xml, .mxl) and MIDI files from MuseScore, Sibelius, Finale or Dorico play back faithfully. Scanned printed music (PDF, PNG, JPG) is recognised optically and works well for clean prints; handwritten pages usually cannot be read.
How long does processing take?
A typical 4-minute song takes a few minutes. When many people are using the service you will see your place in the queue and an estimated wait before you commit a credit, and you can come back later with your secret key.
What happens to my files?
They are processed on our server and deleted automatically one hour after your results are ready, or sooner if you delete them. We do not use your music to train models. See the privacy policy.
Refunds?
If processing fails, your credit is returned automatically. If a result is unusable, email us within 7 days and we will refund it. See the refund policy.
One credit · one file · nothing recurring
Hear your song one part at a time.
Upload a recording or a music sheet. Your first results are minutes away.
