Audio Output

Module ID: output.audio Category: Output Header Color: Red

The Audio Output module

Description

The Audio Output module is the final destination for your audio signal, sending sound to your computer's audio interface. It provides master level control, metering, and a built-in limiter to prevent clipping.

Every patch that makes sound needs exactly one Audio Output module.

Inputs

Outputs

This module has no outputs—it sends audio to the system.

Parameters

Display Elements

Level Meters

Stereo LED-style meters showing:

• Green: Safe levels (-∞ to -6 dB)
• Yellow: Moderate levels (-6 to -3 dB)
• Red: Hot levels (-3 to 0 dB)
• Clip indicator: Flashes on limiting/clipping

Limiter Activity

LED indicates when limiter is actively reducing gain.

How It Works

1. Mixing: Left, Right, and Mono inputs are summed appropriately
2. Level: Master level is applied
3. Limiter: If enabled, prevents signal from exceeding threshold
4. Output: Signal is sent to the audio hardware

Input Routing

• Left only: Duplicated to both outputs (mono)
• Right only: Duplicated to both outputs (mono)
• Mono only: Sent to both outputs
• Left + Right: True stereo
• All three: Mono added to stereo

Usage Tips

Basic Connection

Simplest setup—one source to mono:

[VCA] ──> [Output Mono]

Sound comes from both speakers equally.

Stereo Connection

True stereo from stereo effects:

[Delay Left] ──> [Output Left]
[Delay Right] ──> [Output Right]

Mono + Stereo

Add a mono source to a stereo mix:

[Bass VCA] ──> [Output Mono]
[Pad Left] ──> [Output Left]
[Pad Right] ──> [Output Right]

The bass appears center, pad is stereo.

Proper Gain Staging

For best sound quality:

1. Keep individual module outputs at reasonable levels
2. Use VCAs and mixers to control levels
3. Set Output Level near 0 dB
4. Watch for limiter activation—occasional is fine, constant indicates too hot

Limiter Usage

The built-in limiter prevents harsh digital clipping:

Limiter On (recommended):

• Peaks are caught and reduced
• Protects your ears and speakers
• Slight compression on peaks

Limiter Off:

• True clipping on overs
• Harsh digital distortion
• May be desired for effect

Monitoring Levels

Watch the meters while working:

Avoiding Clipping

If limiter is constantly engaged:

1. Lower Level knob on Output module
2. Lower levels earlier in the signal chain
3. Use VCAs to control dynamics
4. Consider a compressor before output

Testing Patches

When building patches:

1. Start with Output Level low
2. Gradually increase while playing
3. Find a comfortable level
4. Leave headroom for dynamics

Multiple Sound Sources

When mixing multiple voices:

[Voice 1] ──> [Mixer Ch 1]
[Voice 2] ──> [Mixer Ch 2]
[Mixer] ──> [Output Mono]

Use a mixer before output rather than connecting multiple sources.

Connection Examples

Simple Mono Synth

[Oscillator] ──> [Filter] ──> [VCA] ──> [Output Mono]

Stereo Synth with Effects

[Synth] ──> [Reverb L] ──> [Output Left]
            [Reverb R] ──> [Output Right]

Full Mix

[Bass] ──> [Mixer Ch 1]
[Lead] ──> [Mixer Ch 2]
[Pad L/R] ──> [Mixer Ch 3/4]
[Mixer L] ──> [Output Left]
[Mixer R] ──> [Output Right]

Troubleshooting

No Sound

1. Check that Output module exists in patch
2. Verify inputs are connected
3. Check Level knob isn't at minimum
4. Verify system audio output settings
5. Check speakers/headphones are connected
6. Use Oscilloscope to verify signal is reaching Output

Distorted Sound

1. Lower Level knob
2. Watch for constant limiter activation
3. Reduce levels earlier in chain
4. Check for feedback loops in patch

One Channel Only

1. Check if only Left or Right is connected
2. Verify stereo effect settings
3. Use Mono input for mono sources

Audio Glitches/Dropouts

1. Reduce patch complexity
2. Build with release mode (cargo run --release)
3. Close other audio applications
4. Check audio buffer settings

Technical Notes

Sample Rate

Operates at system audio sample rate (typically 44.1 kHz or 48 kHz).

Bit Depth

Internal processing at 32-bit float, converted to system format on output.

Latency

Minimal latency determined by audio buffer size. Lower buffer = lower latency but higher CPU.

Tips

1. One output module per patch: Multiple outputs will conflict
2. Use the limiter: It's there to protect you
3. Watch your levels: Meters are there for a reason
4. Gain stage properly: Don't rely on the limiter for level control
5. Start quiet: You can always turn up, but can't unhear loud surprises

Related Modules

• VCA - Level control before output
• Mixer - Combine signals before output
• Compressor - Dynamics control before output
• Oscilloscope - Visualize what you're sending