StageStem Help & Troubleshooting

Support guide for StageStem — Stem Editor & Bouncer for macOS

1. Overview

StageStem is a macOS audio editor built around multitrack stem assembly and bouncing. It is designed for live sound, theater, broadcast, and any workflow that needs carefully arranged audio delivered as stems — particularly multichannel files for QLab or separate per-track files for a mixing engineer.

The main window has three areas:

• Transport Bar — playback controls, time display, output meters, and tool buttons at the top.
• Timeline — track headers on the left, clip lanes to the right, and a ruler across the top.
• Inspector — a slide-in panel on the right for detailed clip and track settings.

A status bar at the very bottom shows a project summary and quick-access controls for snap, follow-playhead, and the inspector toggle.

2. Importing Audio

Drag and Drop

Drag one or more audio or video files from Finder directly onto the StageStem window. Each file creates a new track and a clip placed at the beginning of that track. If the file’s sample rate differs from the project rate, StageStem resamples it in the background.

File Import Panel

Use ⌘O or the File › Import Audio… menu item to open a standard file picker. You can select multiple files in one go.

Supported Formats

Any format macOS can read — WAV, AIFF, CAF, MP3, AAC, FLAC, and audio tracks from video files (MP4, MOV, etc.).

Media Cache

StageStem keeps a normalized float32 cache of every imported file so playback is sample-accurate regardless of the source format. The original file is never modified. If you move or delete the original file, StageStem uses a saved security bookmark to try to reopen it; if that fails, the clip will appear but produce silence.

3. The Timeline

Playhead & Transport

Click anywhere on the ruler to move the playhead. The transport bar buttons control playback:

Button	Keyboard	Action
⏮ Return to Start	Return	Jump to 00:00.000
▶ Play / ⏸ Pause	Space	Toggle playback at the current position
⏹ Stop	—	Stop and return to where playback began
⏭ Go to End	—	Jump to the end of the last clip

Zooming

Use ⌘+ and ⌘− or the magnifying glass buttons in the toolbar to zoom in and out. Pinch-to-zoom on a trackpad is also supported.

Scrolling

Scroll horizontally to move through time, vertically to move through tracks. Enable Follow Playhead in the status bar (or ⌘F) to have the view automatically scroll to keep the playhead visible during playback.

Snap

With Snap enabled, clip edges, the playhead, and the tempo grid act as magnetic points during dragging. Hold ⌥ Option at any time while dragging to temporarily bypass snap.

Loop Playback

1. Move the playhead to where you want the loop to begin and click L in the toolbar.
2. Move the playhead to the loop end point and click R.
3. Click the Loop button (or press ⌘L) to enable looping.
4. Alternatively, hold ⌘ and drag on the ruler to draw the loop region directly.

Tempo Grid

Set a project BPM and time signature via File › Project Settings. When BPM is non-zero, the ruler displays bar lines and the snap grid aligns to beats and bars.

Markers

Right-click on the ruler to add a named marker at that position. Markers appear as colored flags on the ruler. Click a marker to jump the playhead to it. Right-click a marker to rename or delete it.

4. Track Controls

Track Header Buttons

Button	What it does
M (orange)	Mute — silences the track during playback and excludes it from bounces.
S (blue)	Solo — plays only soloed tracks during monitoring. Solo has no effect on bounces.
ST / MO	Toggle stem width between Stereo (2 channels) and Mono (1 channel) in the bounce output.
A (purple)	Show or hide automation lanes below the clip area.

Volume Slider

When the track height is tall enough, a volume slider appears in the header. Drag it to adjust level from −60 dB to +12 dB. The current level is always shown as a number in the top-right corner of the header. You can also set exact values in the Inspector.

Per-Track Level Meters

Two small meters in each header show live L/R output levels during playback. A red dot indicates clipping.

Renaming a Track

Double-click the track name to edit it inline. Press Return or click away to confirm.

Track Context Menu

Right-click a track header to access:

• Rename — same as double-clicking the name.
• Color — choose from eight palette colors. You can also set a fully custom color from the Inspector.
• Move Up / Move Down — reorder tracks (also changes channel assignment in the bounce).
• Duplicate Track — creates a copy of the track and all its clips.
• Delete Track — permanently removes the track and its clips.

5. Editing Clips

Moving Clips

Click and drag a clip to move it in time or across tracks. With snap enabled, the clip will snap to nearby clip edges, the playhead, and the grid. Hold ⌥ Option while dragging to bypass snap.

Trimming

Hover over the left or right edge of a clip until the cursor changes to a resize arrow, then drag. Trimming the head reveals or hides earlier content from the source file — the audio underneath stays fixed in time, only the visible window changes.

Splitting

Move the playhead to where you want to cut, then press ⌘B or click Split in the toolbar. All selected clips (or all clips across all tracks if nothing is selected) are cut at the playhead position.

Selecting Clips

• Click a clip to select it.
• Hold ⇧ Shift or ⌘ and click to add to the selection.
• Click an empty area of a track lane to deselect.

Copy, Cut & Paste

Standard ⌘C, ⌘X, ⌘V work on the current selection. Pasted clips land at the same relative time offset from the current playhead position.

Deleting Clips

Press ⌫ Delete to remove selected clips, leaving a gap. To delete and slide subsequent clips back to fill the gap, use Delete and Close Gap in the Inspector (visible when multiple clips are selected).

Clip Properties (Inspector)

Select a clip and open the Inspector (⌥⌘I) to access:

• Name — a label displayed on the clip in the timeline.
• Start — exact timeline position. Enter in seconds (12.5) or MM:SS.mmm format (01:23.400).
• Length — clip duration.
• Source Offset — how far into the source file the clip begins.
• Fade In / Fade Out — duration in seconds, with four curve shapes: Linear, Equal Power, S-Curve, or Exponential.
• Gain — per-clip level trim from −48 dB to +12 dB.
• Speed — playback rate from 0.25× to 4×. Pitch is not altered; the clip occupies less or more timeline time.
• Color — optional per-clip color override (independent of the track color).

Undo / Redo

Every edit is undoable. Use ⌘Z to undo and ⌘⇧Z to redo. The undo history is per-window and is cleared when the project is closed.

6. Recording

Click Record in the toolbar or press ⌘R to open the recording sheet.

Microphone / Audio Interface Recording

1. Select Microphone at the top of the sheet.
2. Choose your input device from the dropdown. All Core Audio input devices are listed, including USB and Thunderbolt interfaces.
3. Set the number of channels to capture (up to the device’s maximum).
4. If recording more than 2 channels, choose whether to place them as Mono (1 channel per track) or Stereo (2 channels per track) tracks.
5. Click Start Recording. The sheet shows a timer and a live input meter.
6. Click Stop & Import (or press Escape) to finish. The recorded file is automatically imported and placed at the current playhead position.

System Audio Capture

1. Select System Audio at the top of the sheet.
2. Choose the application or audio source to capture from the dropdown.
3. Click Start Recording. A new stereo track is created when you stop.

7. Tone Generator

Click Tone in the toolbar to open the Tone Generator. It creates a rendered audio clip and places it as a new track.

Settings

Setting	Options
Waveform	Sine, Square, Triangle, Sawtooth, White Noise, Pink Noise
Frequency	Any value in Hz. Presets: 50, 60, 100, 440, 1000, 10000 Hz. (Not applicable to noise waveforms.)
Duration	Any length in seconds. Presets: 1 s, 5 s, 10 s, 30 s, 60 s.
Level	dBFS. Presets: −20, −18, −14, −6 dBFS.
Channels	Mono or Stereo.
Fade In / Fade Out	Duration in seconds (default 10 ms to avoid clicks).
Placement	Place at current playhead position, or at timeline zero.

8. SMPTE LTC Generator

Click SMPTE LTC in the toolbar to generate a Linear Timecode audio track.

Settings

• Frame Rate — 23.976, 24, 25, 29.97 DF, 29.97 NDF, or 30 fps.
• Start Timecode — the timecode value encoded at the first sample (HH:MM:SS:FF).
• End Timecode — the timecode value at the last sample. Must be after the start.
• Placement — place at the current playhead or at timeline zero.

The generated LTC audio is rendered in full and placed on a new track called SMPTE LTC. Route this track’s bounce output to any output feeding a timecode-capable device or software.

9. Frequency Splitter

Right-click any clip and choose Split by Frequency to open the Frequency Splitter. This processes the clip and creates multiple new tracks, each containing only audio in a specific frequency band.

Presets

Preset	Bands
2-Band	Low, High
3-Band	Bass, Mid, High
5-Band	Sub Bass, Bass, Low Mid, High Mid, High

Each band is automatically assigned a distinct track color. The processing is done offline — playback is not interrupted. The original clip remains unchanged on its original track.

10. Audio Unit Effects

StageStem supports any Audio Unit v2/v3 effect plugin installed on your Mac. Effects are processed in real time during playback and are baked into the bounce.

Adding an Effect

1. Select a track by clicking its header.
2. Open the Inspector (⌥⌘I).
3. Under Effects, click the + button.
4. Browse by manufacturer or category and double-click a plugin to add it.

Managing the Effects Chain

• Reorder — drag effects up or down the list to change processing order.
• Bypass — click the filled circle icon next to an effect to bypass it without removing it. Click again to re-enable.
• Open Editor — click the slider icon to open the plugin’s native GUI in a floating panel.
• Remove — click the red minus icon and confirm in the dialog.

11. Automation

Automation lets you draw parameter changes over time directly on the timeline.

Enabling Automation Lanes

Click the A button in the track header (or toggle Show in the Inspector’s Automation section) to reveal the automation lanes below a track’s clip area.

Parameters

• Volume — from −60 dB to +12 dB.
• Pan — from full left (−1) to full right (+1).
• Speed — clip playback rate from 0.25× to 4×.

Drawing Points

Click anywhere in an automation lane to add a control point. Drag existing points to move them. Points are connected by straight lines (linear interpolation). To delete a point, right-click it.

Auto-Level

Click Auto-Level in the Inspector’s Automation section to have StageStem analyze the audio on the track and automatically write volume automation targeting −3 dBFS. This is useful for leveling a dialogue or narration track without manual riding.

Clearing Automation

Click Clear next to any parameter lane in the Inspector to remove all points for that parameter.

12. Bouncing & Export

Click Bounce Stems in the toolbar or press ⌘E to open the Bounce sheet.

Bounce Modes

Mode	What you get	Best for
Single Multichannel File (Stems)	One interleaved audio file. Each track occupies its own output channel(s).	QLab, Qlab, live show playback systems that assign channels to outputs.
Separate File per Track	A folder of time-aligned files — one per track, all the same duration.	Delivering stems to a mix engineer or loading into another DAW.
Stereo Mixdown	Everything folded to two channels, exactly as it sounds during monitoring.	Reference mixes, demos, or streaming delivery.

Format Options

Setting	Options
Format	WAV, AIFF, CAF, MP3 (MP3 is not available in multichannel stem mode)
Bit Depth	16-bit integer, 24-bit integer, 32-bit float
MP3 Bitrate	128, 192, 256, or 320 kbps
Sample Rate	Fixed to the project sample rate (shown for reference)
Tail	Seconds of silence added after the last clip — useful for reverb tails (0–30 s)

Muted Tracks & Channel Map

Muted tracks are excluded from the bounce by default. Enable Include muted tracks if you want them in the output. For multichannel stem mode, you can also write a plain-text channel map file alongside the audio file — useful for handing off to a sound designer who needs to know which channel is which track.

Reading the Bounce Report

After a successful bounce, the sheet shows a per-stem summary with the peak level in dBFS. A red warning means that stem exceeded 0 dBFS and will clip in any fixed-point format. To fix this: lower the track’s level in the Inspector and bounce again, or switch to 32-bit float which has no clipping ceiling.

13. Keyboard Shortcuts

Shortcut	Action
Space	Play / Pause
Return	Return to start (00:00.000)
⌘B	Split clips at playhead
⌫	Delete selected clips
⌘C	Copy selected clips
⌘X	Cut selected clips
⌘V	Paste clips
⌘Z	Undo
⌘⇧Z	Redo
⌘L	Toggle loop playback
⌘+	Zoom in
⌘−	Zoom out
⌘R	Open recording sheet
⌘E	Open bounce / export sheet
⌥⌘I	Show / hide the Inspector panel
⌥ + drag	Bypass snap while dragging a clip or edge
⌘ + drag on ruler	Draw the loop region

14. Troubleshooting

No sound during playback

• Check that no tracks are muted (orange M button in the track header).
• Check the output meters in the transport bar. If they move but you hear nothing, check your macOS audio output in System Settings › Sound.
• Check that StageStem’s volume is not muted in macOS volume mixer (hold ⌥ and click the speaker in the menu bar, or check in Audio MIDI Setup).
• If a red engine error appears in the status bar, try quitting and relaunching the app.

Clips play silence but waveforms are visible

• The source file has been moved, renamed, or deleted. StageStem will attempt to use a saved bookmark to find it. If it cannot, the clip plays silence.
• Re-import the file and replace the clip, or locate the file at its original path.
• If the file is on an external drive, make sure the drive is mounted before opening the project.

Import takes a very long time

• Large files (especially long video files or high-sample-rate audio) must be fully decoded and resampled on import. This is a one-time cost — subsequent opens are instant.
• Avoid importing from slow network drives. Copy files locally first for faster decoding.

Recording device not appearing in the list

• Make sure StageStem has Microphone permission: System Settings › Privacy & Security › Microphone.
• Click the refresh button in the device picker, or close and reopen the recording sheet.
• Some USB audio interfaces require you to select them in Audio MIDI Setup before they appear in third-party apps.
• If the device still doesn’t appear, try unplugging and reconnecting it.

System Audio source list is empty

• StageStem needs Screen Recording permission to enumerate system audio sources. Go to System Settings › Privacy & Security › Screen Recording, enable StageStem, then quit and relaunch the app.
• If you granted permission and then revoked it, the list will be empty until the permission is restored and the app is relaunched.

Audio Unit plugin not appearing in the picker

• Only installed Audio Unit (AU) plugins appear. VST and AAX formats are not supported.
• After installing a new plugin, relaunch StageStem so macOS can register it.
• Some older AU plugins are 32-bit only and will not load on macOS Ventura or later. Contact the plugin manufacturer for an updated version.
• If the plugin appears in the list but the editor button is greyed out after adding it, the plugin failed to instantiate. Check the plugin is properly activated/licensed.

Bounce produces silence or an empty file

• Check that at least one track is not muted. If all tracks are muted, the bounce sheet will warn you.
• Make sure clips actually have content — check waveforms are visible in the timeline.
• If the source files were moved since import, clips may produce silence (see above).

Bounce report shows clipping (red peak warning)

• Lower the volume of the affected track in the Inspector (drag the Level slider down) and bounce again.
• Alternatively, switch the bit depth to 32-bit float in the bounce sheet — 32-bit float has a headroom far beyond 0 dBFS and will never clip.
• Clip gain can also be reduced per-clip in the Inspector if only one section of the track is loud.

Multichannel stem file won’t load in QLab

• QLab has a practical limit of 24 channels per audio file. StageStem warns you if your channel count exceeds this — use Separate Files mode instead for large track counts.
• Use WAV format for maximum compatibility. CAF files may not be supported in all versions of QLab.
• Check the channel map text file (if you enabled it) to confirm which channels correspond to which tracks, and match them to your QLab output patch.

Automation curves are not audible during playback

• Make sure the automation lane is enabled — click the A button on the track header to show lanes, then verify points exist in the parameter you expect to be moving.
• If Speed automation is applied, the visible clip length does not change — only the playback rate is affected during rendering.

The project sounds different after a bounce than during playback

• Solo is ignored in the bounce — all non-muted tracks are included. If you were monitoring with solo active, the bounce will include all non-muted tracks.
• The bounce renders at the full project sample rate regardless of your audio interface’s current rate. There should be no difference in quality.
• Confirm that no Audio Unit plugin is producing a different result during offline rendering. Some third-party plugins behave differently in real-time vs. offline processing — this is a plugin issue, not a StageStem issue.

The app is slow or audio is stuttering during playback

• High track counts with multiple CPU-intensive Audio Unit plugins can cause buffer underruns. Try increasing the audio buffer size in your interface’s driver settings.
• Bypass effects that are not needed for the current editing session using the bypass toggle in the Inspector — bypassed effects consume no CPU.
• Quit other audio applications (Logic, Pro Tools, Zoom, etc.) that may be competing for the audio device.

Saving and reopening the project

• StageStem uses standard macOS document saving. Use ⌘S to save, ⌘⇧S to save a copy with a new name.
• The project file stores all track, clip, and effect settings, but not the audio data itself — the original source files must remain accessible. Keep source files in a stable location and avoid renaming or moving them after import.
• Audio Unit preset data is embedded in the project file, so plugins will restore to the same state when the project is reopened — provided the plugin is still installed.

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Still need help? Contact us at info@mickeydesigns.com.