Audio Routing Modes
Signals & Sorcery supports a performance workflow where the performer can audition and generate privately while the audience hears only approved output. Routing is explicit and predictable on macOS (Core Audio), with no paid dependencies required.
Concepts
Buses
- Cue Bus: Private monitoring for the performer (headphones)
- Master Bus: Public output (PA or stream)
- Monitor Mix (optional): What the performer hears when blending Cue + Master
Channel Pairs
A "channel pair" is a stereo output pair on your audio interface:
| Pair | Outputs |
|---|---|
| A | 1-2 |
| B | 3-4 |
| C | 5-6 |
| etc. | ... |
Mode 1: Solo Mode
One output device, one stereo pair
Use Case
A solo user on a laptop with a single stereo output can listen to the composition deck (Cue) or Master output—but only one at a time.
Minimum Hardware
- Any Mac with a single stereo output (built-in, USB dongle, etc.)
- Headphones or speakers
Routing
- SAS uses exactly one stereo output pair (e.g., outputs 1-2)
- Select a Solo Listen Source:
CueorMaster - SAS routes the selected source to the stereo pair
- All other sources are muted
Settings
| Setting | Description |
|---|---|
| Output Device | CoreAudio device to use |
| Output Pair | Channel pair (default 1-2) |
| Solo Listen Source | Which bus to monitor |
Mode 2: Performance Mode
Cue to headphones, Master to PA
Use Case
Performer generates and auditions privately in headphones while the audience hears only approved Master output on the PA system.
Hardware Requirements
Performance Mode requires a CoreAudio device with two independent stereo outputs:
- One for Cue (headphones)
- One for Master (PA)
Recommended:
- Multi-output USB audio interface with at least 4 outputs (two stereo pairs)
- USB audio interface with built-in headphone output (appears as a CoreAudio device)
Routing
| Bus | Destination | Example |
|---|---|---|
| Cue | Headphones pair | Outputs 1-2 |
| Master | PA pair | Outputs 3-4 |
Device Capability Check
When selecting an output device, SAS detects the number of output channels. If fewer than 4 outputs are available:
WARNING
Performance Mode requires two independent stereo outputs (Cue + Master). Select a device with at least 4 outputs.
Settings
| Setting | Description |
|---|---|
| Output Device | CoreAudio device |
| Cue Output Pair | Channel pair for headphones |
| Master Output Pair | Channel pair for PA |
| Headphone Blend | Optional mix of Cue + Master |
Important
- Cue never leaks to Master output
- Master never interrupts Cue auditioning
- Switching scenes does not cause outputs to swap
Mode Comparison
| Feature | Solo | Performance |
|---|---|---|
| Minimum outputs | 2 | 4 |
| Simultaneous Cue + Master | No | Yes |
| Best for | Practice, solo production | Live PA performance |
Error Handling
Device Unplugged
If the selected device is unplugged, SAS will:
- Fall back to built-in output
- Switch to Solo Mode
- Display a warning
Insufficient Outputs
If the selected device doesn't have enough outputs for the chosen mode:
- Performance mode will be disabled
- User must select a device with more outputs or switch to Solo Mode
Configuration Reference
Audio settings are stored with the following structure:
| Key | Values | Description |
|---|---|---|
mode | solo, performance | Current routing mode |
outputDeviceId | string | Selected CoreAudio device |
soloOutputPair | number | Channel pair for Solo mode |
cueOutputPair | number | Channel pair for Cue bus |
masterOutputPair | number | Channel pair for Master bus |
soloListenSource | cue, master | Solo mode source selection |