Stemly – User Manual
User Manual

Stemly

Complete guide — from first launch to live performance. Step by step.

1 Requirements & hardware

ItemRequirement
DeviceiPad (recommended) or iPhone
SystemiOS 17.6 or later
USB audio interfaceAny USB-C interface with multi-out support (e.g. Behringer XR18, Allen & Heath, Roland)
ConnectionUSB-C cable directly from iPad to mixer or interface
USB hub (recommended)Hub with PD input (Power Delivery — charges device during show) + USB-A port for audio interface or digital mixer. For older Apple devices: Apple Lightning OTG Camera Adapter.
Audio filesWAV, AIFF, MP3 — stereo or mono
🎧 Recommendation: iPad connected via USB cable to an FOH mixer delivers a lossless digital signal with zero interference — the foundation of a rock-solid live set.
✈️ Airplane Mode — always on stage. Switch every device to Airplane Mode before the show. Stemly and Stemly Remote communicate via Bluetooth — Airplane Mode does not block this connection. You gain: zero incoming calls, no push notifications, no Wi-Fi radio interference with your audio chain.

2 First launch — selecting a folder

Before you can build songs, you need to tell the app where your audio files are. This is done once in Settings.

  1. Open Stemly on your iPad or iPhone.
  2. Go to the Settings tab (icon at the bottom of the screen).
  3. Tap Audio Files.
  4. Select a folder on local iPad storage — this is the only safe source for live performance. Files from iCloud or Dropbox may not load without internet or can cause delays at the worst moment.
  5. Tap Open — Stemly will remember this folder permanently.
  6. Now go to the Project tab to start building your first songs.
💡 Tip: Store your audio files in local iPad storage — this guarantees playback without internet or sync delays, essential for a reliable live show. See the critical note below about which folder to use.
⚠️ Warning: Do not change the audio folder right before a show — tracks will stop being visible until you re-select each file.
🛑 Important — never store your files inside the Stemly app folder.

The folder Files → On My iPad → Stemly is the app’s own sandbox. When you uninstall Stemly, this entire folder is permanently deleted — along with every audio file, lyrics text and database backup stored inside it.

Recommended folder structure: Create your own folder outside the app — for example “Stemly Copy” — directly in On My iPad or in iCloud Drive. Keep all three things there:
•  Audio stems (WAV / AIFF / MP3)
•  Database backup (JSON file — exported from Settings)
•  Lyrics text files (RTF / TXT)

This folder is yours. It survives app updates, reinstalls and full device restores.

3 Preparing your audio files

Each stem in a song is a separate audio file. Make sure your files are ready before importing.

Supported formats

FormatNotes
WAV 48kHz / 24-bitBest choice for live performance — recommended
WAV 44.1kHz / 16-bitWorks correctly, smaller file size
AIFFEquivalent alternative to WAV
MP3Supported — smaller files, useful on storage-limited devices (e.g. iPhone 64 GB). Not recommended for professional live use due to lossy compression.
🎤 Stereo splitting: Stemly automatically splits every stereo file into a left channel and a right channel. Each channel is sent to a separate USB output — no manual splitting needed.

File naming

File names can be anything — you assign them to a song manually inside the app. Keeping things organised helps, for example:

01_Kick.wav • 02_Bass.wav • 03_Keys.wav • 04_BackingVox.wav

💡 Tip: Store all stems for one song in a dedicated subfolder, e.g. Stemly/GreatNight/. The file browser in the app lets you navigate subfolders.

4 App structure, tabs & modes

Stemly is organised into main work areas accessible from the tab bar at the bottom of the screen. The visible tabs depend on device and UI mode.

🎼

Project

Build songs here: add stems, set OUT routing, edit TrackName and Vol, save songs to the library.

🎵

Songs

Live playback area. Song library, Single / Queue workflow, PLAY and STOP, live mixer and queue.

📋

PlayList

Build and reorder setlists. Available in Advanced mode and on iPad layouts.

📚

Lyrics

Lyrics editor (TXT/RTF), QR sharing and wireless display on any device with a browser.

⚙️

Settings

Audio folder, USB device config, database export/import, AutoLyrics and UI mode.

📱 Simple vs Advanced: Simple shows only Project, Songs and Settings. Advanced unlocks the full stage workflow including PlayList and Lyrics.
📱 iPhone vs iPad: On iPhone the layout is vertical (file browser on top, channel strips below). On iPad — horizontal, both panels side by side, with more live controls visible at once. Single and Queue mode buttons are only available on iPad.

5 Creating your first song

A song is a collection of audio stems playing simultaneously. Each stem can be routed to a different USB output channel on your mixer.

  1. Open the Project tab.
  2. In the left panel (File Browser), tap an audio file — it is added automatically as a new stem.
  3. In the Channel Strip, set the USB output number (OUT) for each stem.
  4. Use TrackName to enter a short alias for the live mixer if needed.
  5. Set Vol per stem. For true stereo files and linked 2x mono pairs, edit Vol and TrackName only on the left channel — the right side follows automatically.
  6. Enter a title for the song and tap Save Song to save it to the global song library.
💡 Library vs playlist: Saving in Project creates or updates a song in the main library. Playlists are built later from saved songs.
💡 Test before saving: Press Play in the Project tab to test the song before saving. You don’t need to be connected to a mixer — audio plays through the iPad speaker.

6 USB channel routing

This is the heart of Stemly — each stem goes to a separate USB output, which feeds its own channel on your mixer. Every stereo file is automatically split into a left channel (L) and a right channel (R) — each sent to its own USB output line.

Example routing for 4 stereo stems:

StemUSB outputMixer channel
DrumsOUT 1+2CH 1–2
BassOUT 3+4CH 3–4
KeysOUT 5+6CH 5–6
Backing VoxOUT 7+8CH 7–8
💡 Tip: Set your outputs and volume on the first song and save it as an Out/Vol Preset (see section 11). Load it with one tap for every new song.
⚠️ Mono track placement — important: The Stemly mixer groups channels in pairs: 1+2, 3+4, 5+6… A mono track occupies one channel but still takes up one slot in a fader pair. If you place a mono Bass on CH 1 and stereo Drums on CH 2+3, the bass and the Drums L will share fader pair 1+2 — while Drums R will be alone on pair 3+4. Always place stereo tracks first (CH 1+2, 3+4…) and mono tracks at the end. This keeps every fader pair clean and correctly linked.
⚠️ Warning: Make sure your mixer is set to receive signal from USB — on some models you need to switch the channel source from Analog to USB.

7 Creating playlists & setlists

A playlist is a collection of songs. You can have multiple playlists — one per tour, one per venue, one per set.

Adding songs to a playlist

  1. In the Songs tab, tap “Build Playlist” (orange button at the top of the song list). Checkboxes appear next to each song.
  2. Tap songs to select them — a checkbox appears next to each selected song.
  3. Tap “Add X to Playlist” to add the selected songs to an existing playlist or create a new one.

Reordering and deleting songs in a playlist (iPad)

  1. Open the PlayList tab (iPad only). In the left column, find the playlist you want to edit.
  2. Tap the pencil icon (✍) on the right side of the playlist row to enter Edit mode.
  3. Drag songs to reorder them, or swipe left to delete a song from the playlist.
  4. Tap “Done” to exit Edit mode.
💡 Tip: Removing a song from a playlist does not remove it from the global Songs library. The library and playlists are separate.

8 Live playback — Song tab

This is where you work during a show. All your songs, full control.

  1. Tap a song name — it gets loaded and prepared for playback.
  2. On iPad you can choose Single or Queue above the mixer. Single works with one song at a time. Queue lets you prepare the next songs in order.
  3. Press PLAY (requires 2 taps) — playback starts immediately.
  4. Use the A–Z bar on the right to jump instantly to any song.
  5. Press STOP (requires 3 taps) to stop playback.

Song list indicators

IndicatorMeaning
Green + play iconCurrently playing song
Queue number badgeSong position in the queue
Subtle blue highlightCurrently selected / loaded song
Orange highlight + “NEXT” labelSong queued from Stemly Remote (Android) — will load automatically after current song ends
⚠️ Stage safety: PLAY requires 2 taps, STOP requires 3. This is intentional — it prevents accidentally stopping the music mid-show. You can change the tap count in Settings.

Single vs Queue mode (iPad)

Above the mixer on iPad you will find two mode buttons:

ModeBehaviour
SingleOne song at a time. Selecting a new song immediately replaces the current one.
QueueSongs are added to a numbered queue (up to 10). The next queued song loads automatically after the current one ends.

Adding songs to a playlist from the Songs tab

On iPad, tap “Build Playlist” (button in the header bar) to enter selection mode. Checkboxes appear next to songs; after selecting them, tap “Add X” to assign them to an existing playlist or create a new one. On iPhone this shortcut is hidden to keep the live layout simple.

Stemly Remote — wireless remote control

Stemly Remote is a companion app for iPad/iPhone that acts as a wireless remote for Stemly. It connects via Wi-Fi (MultipeerConnectivity) — no internet required, just the same local network or hotspot. In Airplane Mode both devices communicate via Bluetooth.

Connecting

  1. Launch Stemly on the host device (the one connected to the mixer).
  2. Launch Stemly Remote on the remote device.
  3. Connection is automatic — a green dot in the top bar confirms it.
  4. Stemly Remote immediately downloads the full playlist and song library from the host.
🔄 Auto-reconnect: If the connection drops, Stemly Remote retries automatically every 2 seconds. No action needed.

Top bar

IndicatorMeaning
🟩 Green dot + “Connect to Stemly”Connected to host
🔴 Red dot + “Searching…”Looking for host
▶ NOW PLAYINGHost is currently playing
■ STOPHost is stopped

View toggle — Song / Playlist

ViewWhat it shows
View Song (orange)All songs from all playlists, sorted A–Z. Use the alphabet bar on the left to jump instantly.
View Playlist (green)Playlist list → tap a playlist → its songs appear with the alphabet bar.

Selecting a song

Tap any song in either view → it loads on the host (Stemly) and the lyrics appear automatically in the right column (yellow header = current song title).
The lyrics column also updates automatically when the host changes a song from its own screen, or when Stemly Remote just connected.

📝 Lyrics require TXT files placed in: Files → On My iPad → Stemly → Lyrics. No folder selection needed — the location is fixed.

Queuing during playback

When the host is NOW PLAYING:

  • Tapping a song queues it (yellow highlight) — it does not interrupt playback.
  • Tap the trash icon 🗑 next to a queued song to remove it from the queue.
  • When the host stops → Stemly Remote automatically loads the queued song. Press PLAY twice to start.

PLAY / STOP confirmation

ButtonTaps requiredSequence
PLAY2PLAY → PLAY? → starts
STOP3STOP → STOP? → STOP?? → stops
⚠️ Double/triple confirmation is intentional — it prevents accidentally stopping the show. The tap count can be changed in Stemly Settings.

Auto-switch to Song view

When the host starts playing, Stemly Remote automatically switches to Song view after 2 seconds — regardless of which view was active or the Auto-Lyrics setting in Stemly.

Device combinations — iOS

Host (Stemly)Remote (Stemly Remote)
iPadiPhone
iPhoneiPad
iPadiPad
iPhoneiPhone

One host supports one Stemly Remote at a time.

Stemly Remote Android

Stemly Remote is also available as an Android app (eu.bandistudio.stemlyremote.android). It connects to the Stemly host via Wi-Fi (local network or hotspot) and provides the same song browsing and queue control as the iOS version.

FeatureAndroid Stemly Remote
ConnectionWi-Fi — same local network as the Stemly host (iPad/iPhone)
Song listFull A–Z song library, alphabet bar for quick navigation
QueueingTap a song while host is playing → it appears highlighted orange with “NEXT” label in the iPad Songs list
Playlist viewBrowse and select by playlist
📷 NEXT on iPad: When you queue a song from Stemly Remote Android, the Stemly iPad immediately highlights that song in orange with a white “NEXT” label — visible to the performer at a glance.

Best practices

  • Set Auto-Lock → Never (Settings → Display & Brightness) on the Stemly Remote device — MultipeerConnectivity does not work when the screen is locked.
  • Enable Background Audio on the host (Stemly) — playback continues even if the host screen turns off.
✈️ Airplane Mode + Stemly Remote: Both devices can be in Airplane Mode — Stemly Remote connects via Bluetooth. Confirmed working: iPhone as host (connected to mixer via USB hub) + iPad as remote, both in Airplane Mode.
🔌 USB hub for the host device: Use a hub with a PD port (Power Delivery) and a USB-A port. Connect: PD port → charger or power bank; USB-A port → audio interface or digital mixer. For older Apple devices, use an Apple Lightning OTG Camera Adapter. This lets your iPhone or iPad stay charged for the entire show while sending audio to the mixer.

9 Live stereo mixer

The faders in the Song tab let you adjust volume for each stereo channel pair in real time — without stopping playback.

ActionResult
Drag fader upIncrease volume for that channel pair
Drag fader downDecrease volume
Number below faderCurrent volume in percent
Red faderChannel muted
💡 Tip: Faders are grouped in stereo pairs matching your USB output channels. OUT 1+2 is one fader, OUT 3+4 is the next, and so on.

Splitting a stereo pair into mono channels

Each fader pair (e.g. 1+2, 3+4) has a 🔗 chain icon in its header:

Icon stateMeaning
🔗 greyChannels linked (stereo) — one fader controls both
Tap grey iconPair splits into two independent mono faders
🔗 orangeChannels unlinked (mono) — each has its own fader and level
Tap orange iconPair links back to stereo (volume averaged)
💡 Example: Channels 1–4 are stereo pairs, but channels 5 and 6 are two independent mono channels — split the 5+6 pair and control each separately.

Light header bar above the faders

The area showing the channel number and 🔗 icon has a slightly lighter rounded background. It serves two purposes:

  • Visually suggests the fader row can be scrolled horizontally (there may be more faders than visible)
  • Practically gives a safe area to swipe — touching a fader immediately changes volume, while swiping on the light header bar scrolls the view without accidentally moving any levels

Channel alias

Every fader can have a short label — an alias — displayed above the channel number during your show.

Setting an alias (PROJECT tab)

In the track edit view, between the filename and the S (Solo) button, a small text field appears with the placeholder NameTrack. Enter a short name, for example:

snr  •  kic  •  bas  •  voc  •  gt1  •  key

  • Maximum 8 characters
  • Alias is saved with the song
  • Leave it empty — the fader looks normal with no changes

Displaying the alias above the fader (SONG tab)

When an alias is set, it appears above the channel number in the fader header — in blue bold monospace font. Visible on both stereo faders (1+2) and mono faders (after unlinking a pair).

Fader header — fixed height

The grey header area has a fixed height regardless of whether an alias is set. This means:

  • The volume fader always starts at the same position
  • Switching stereo ↔ mono never shifts the fader
  • The taller header gives a more comfortable surface for swiping horizontally — without risk of accidentally adjusting volume

10 Song lyrics

Stemly has a built-in Wi-Fi lyrics server. After pressing PLAY the app automatically switches to the Lyrics tab after 2 seconds (AutoLyrics).

Where to store lyrics files

Lyrics files are stored in the app’s built-in folder — always accessible, no folder selection needed after restart:

Files → On My iPad → Stemly → Lyrics

  • Recommended format: TXT (UTF-8). RTF is also supported.
  • File name must match the song title in the app (case-insensitive, tolerant of special characters).
  • Green ✓ icon next to a song = lyrics file found. Red ! icon = file missing.
  • Long-press a song title in the right-hand list → opens the lyrics file manager for that song.
  1. Place your TXT lyrics files in Files → On My iPad → Stemly → Lyrics.
  2. Make sure the host device is connected to the same local network as the receiving device.
  3. Open the Lyrics tab and use the QR button to share the lyrics page quickly.
  4. The current song’s lyrics appear automatically and change with your song selection or setlist flow.

Network options for lyrics display

Receiving devicesNetwork neededRecommendation
iOS onlyNo extra router neededAll Apple devices connect directly — works in Airplane Mode via Bluetooth / Wi-Fi Direct. Turn on Personal Hotspot on the host if needed.
Android, Windows, other OSShared local Wi-Fi requiredAll devices must be on the same network. Best: bring your own portable router. Do not rely on venue Wi-Fi.
📷 QR code — fastest connection. In the Lyrics tab use the QR button to open the sharing code instantly on screen. Musicians scan it and open the browser without typing any address.
⚠️ Keep the host screen on — never let it sleep during a show. If the screen turns off, the Wi-Fi server pauses and lyrics stop updating.

Recommended: Set Settings → Display & Brightness → Auto-Lock → Never before going on stage.

If the screen did turn off: Wake the host device, then refresh the browser on Android / Windows / Mac — lyrics synchronisation resumes immediately.
⚠️ Red title in the Lyrics tab — title mismatch. If a song’s title does not match the name of its lyrics text file on disk, the title will appear in red.

How to fix: Make sure the song title (as entered in Project) and the lyrics file name on disk are identical.
💡 AutoLyrics: You can disable the automatic switch to lyrics in Settings → AutoLyrics.

11 Out/Vol Presets

A preset saves your entire output channel and volume configuration — load it with one tap into any new song.

How to save an Out/Vol Preset:

  1. In the Project tab, set the output channels and volumes for all stems.
  2. Tap Out/Vol Presets → Save Setting.
  3. Enter a name, e.g. “Standard 4 stereo”, and tap Save.

How to load a preset into a new song:

  1. Add stems to the new song.
  2. Tap Out/Vol Presets → Load Setting and select from the list.
  3. Output channels and volumes are applied automatically — done.

12 Database backup — essential before every show

The Stemly database holds all your playlists, songs, and routing. It’s one JSON file — protect it.

How to back up:

  1. Go to the Settings tab.
  2. Tap Export Database.
  3. Choose where to save: iCloud Drive, AirDrop to Mac, or send by email.

How to restore:

  1. Go to Settings → Import Database.
  2. Select your JSON backup file.
  3. All playlists and songs are restored immediately.
⚠️ Important: The backup does not include your audio files — those live in your folder. The database backup protects only your playlist configuration and routing. Keep the JSON file in iCloud Drive.
🛑 Store your backup outside the app folder. The folder Files → On My iPad → Stemly is deleted with the app. Save your JSON backup to a safe location: iCloud Drive, AirDrop to Mac, or your own folder — for example “Stemly Copy” in the root of On My iPad.

13 Pre-show checklist

Before every performance, verify:

  • Database backed up (Settings → Export Database)
  • All audio files are in the local iPad folder — no missing stems
  • Audio routing tested on the USB device during soundcheck
  • PLAY/STOP tap count checked in Settings
  • Lyrics server started and verified on at least one receiving device
  • Auto-lock disabled: iOS Settings → Display & Brightness → Auto-Lock → Never
  • iPad charged or connected to power via USB hub
💡 Pro tip: Run your soundcheck with Stemly Remote on your iPhone — stand at the mixer and test PLAY/STOP without walking back to the iPad.

14 Audio formats, conversion & track limits

What happens when you play different formats

FormatWhat happensLive show
WAV 48kHzLoaded to RAM — zero processing during playback✅ Ideal
WAV 44.1kHz (converted)Converted once at import, then loaded to RAM✅ Safe
WAV 44.1kHz (no conversion)Plays ~2.4% faster — 4 min song ends 5–6 sec early, tracks desync⚠️ Home only
MP3 (converted to WAV)Decoded once at import, stored as WAV 48kHz✅ Safe
MP3 (no conversion)Real-time decoding on CPU — risk of glitches with many tracks❌ Avoid
⚠️ Golden rule: Convert all files to WAV 48kHz before soundcheck. Stemly offers conversion automatically when you add an MP3 or 44.1kHz file.

RAM usage — how much memory per track

Format1 min mono1 min stereo
WAV 48kHz Float32~11 MB~23 MB
MP3 / 44.1kHz (after conversion)~11 MB~23 MB

Track limits by device (iOS 17.6)

DeviceRAMMax tracks*
iPhone XR · iPad 7th gen · mini 53 GB5–6 tracks
iPhone XS · iPad Air 3rd gen4 GB8–10 tracks
iPhone 12 Pro · iPad Air 4th gen6 GB15 tracks
iPhone 14 Pro · iPad Air M16 GB15 tracks
iPhone 15 Pro · iPad Pro M2/M48–16 GB32 tracks ✓

* Values for 4-minute mono WAV 48kHz tracks. Stereo tracks use 2× the RAM.

Typical live show examples

SetupRAM usedWorks on
6 mono tracks · 4 min~264 MBAll devices
8 tracks (4 mono + 2 stereo) · 4 min~268 MBAll devices
12 tracks (8 mono + 2 stereo) · 4 min~444 MBiPad Air+
20 mono tracks · 5 min~1100 MBiPad Pro M2/M4

15 Bluetooth foot pedal

Stemly supports any Bluetooth foot pedal that pairs as a standard BT keyboard — for example the Joyo JSP-1 or any page-turner pedal used for PDF sheet music. No special drivers or CoreBluetooth setup needed.

How it works

BT pedals pair with iOS just like a Bluetooth keyboard. Once paired, Stemly captures the key events and maps them to stage actions: PLAY, STOP, RESET, NEXT SONG, PREV SONG.

Pairing

  1. Put the pedal in pairing mode (usually hold the button until the LED flashes).
  2. On iPad/iPhone: Settings → Bluetooth → select the pedal from the list.
  3. The pedal is now paired. No action needed inside Stemly — just open the app.

Configuration in Stemly

Tap the pedal icon (🦶) in the Songs tab toolbar to open the Foot Pedal Settings panel.

ActionWhat it does
PLAY / PAUSETriggers the PLAY button (with click-count safety)
STOPTriggers the STOP button (with click-count safety)
RESETStops playback immediately — no double-click required
NEXT SONGReserved for future use
PREV SONGReserved for future use

Assigning a pedal button to an action

  1. In the Foot Pedal Settings panel, find the action row (e.g. PLAY / PAUSE).
  2. Tap SET — the row highlights orange and the status bar shows “Press a key…”
  3. Press the pedal button you want to assign. The key name appears immediately.
  4. Press Escape (or tap Cancel) at any time to abort without saving.
💡 Conflict resolution: If you assign a key that is already used by another action, Stemly automatically removes it from the old action first.

Click mode — PLAY and STOP

PLAY and STOP each have an independent click mode selector:

ModeBehaviour
1 clickSingle pedal press triggers the action immediately
2 clicksTwo presses within 0.8 s required — matches the on-screen PLAY/STOP safety tap count. Default.
⚠️ Stage safety: The default 2-click mode mirrors the on-screen double/triple tap requirement. Use 1-click only if you are confident you won’t accidentally press the pedal during a performance.

Key indicators

While waiting for a second click (2-click mode), a ? appears next to the PLAY or STOP label. If no second press arrives within 0.8 s, the counter resets automatically.

Clearing assignments

  • Tap the icon next to an assigned key to clear that slot.
  • Tap Clear all assignments at the bottom of the panel to reset everything.
💡 Settings are saved automatically in UserDefaults and survive app restarts and device reboots.

Supported pedal models

Any BT pedal that pairs as a standard HID keyboard works. Confirmed examples:

PedalTypical key sent
Joyo JSP-1 (left)← Left Arrow
Joyo JSP-1 (right)→ Right Arrow
Most PDF page-turner pedalsPage Up / Page Down or arrow keys
✈️ Airplane Mode: BT pedals continue to work in Airplane Mode — Bluetooth is not disabled when you toggle Airplane Mode on iOS (you can re-enable BT manually after).

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