O-Comp User Guide
Transparent dynamics control with variable soft-knee
Getting Started
Quick Start
- Download the installer from your Ouaricon Audio account
- Run the installer — it installs both VST3 and AU formats automatically
- Open your DAW and scan for new plugins
- Insert O-Comp on a track
- Enter your license key (OUA-XXXX-XXXX-XXXX) when prompted
System Requirements
| Platform | Details |
|---|---|
| macOS | macOS 10.13+ (Intel and Apple Silicon native) |
| Windows | Windows 10+ (64-bit) |
| RAM | 4 GB minimum, 8 GB recommended |
| Formats | VST3, AU |
| DAW | Any VST3/AU-compatible host |
Installation Paths
macOS:
- VST3:
~/Library/Audio/Plug-Ins/VST3/O-Comp.vst3 - AU:
~/Library/Audio/Plug-Ins/Components/O-Comp.component
Windows:
- VST3:
C:\Program Files\Common Files\VST3\O-Comp.vst3
Interface Overview
O-Comp features a visual interface with real-time feedback for precise dynamics control. The interface combines traditional knob controls with graphical displays for intuitive operation.
Visual Elements
- Transfer Curve Visualization: Shows the compression curve shape based on your Threshold, Ratio, and Knee settings. Provides immediate visual feedback on how compression will be applied.
- LED Meters: Input and output level meters for monitoring signal levels
- Gain Reduction Display: Real-time GR meter shows how much compression is being applied (in dB)
- Envelope Display: Visualizes the detector envelope tracking your audio signal
Design Philosophy
O-Comp is designed for transparency and predictability. It uses a feed-forward detection design (not feedback), meaning the detector analyzes the input signal before compression is applied. This results in more consistent, predictable behavior across different sources and settings.
Parameters
| Parameter | Range | Default | Description |
|---|---|---|---|
| Threshold | -60 to 0 dB | -20 dB | Level above which compression begins. Signals below this are unaffected; signals above are compressed. |
| Ratio | 1:1 to 20:1 | 4:1 | Amount of compression applied. At 4:1, for every 4 dB the signal exceeds the threshold, the output increases by 1 dB. Higher ratios = more compression. |
| Attack | 0.1-100 ms | 10 ms | How quickly compression engages after the signal exceeds the threshold. Faster attack (lower values) = tighter control of transients. Slower attack = lets transients through. |
| Release | 10-1000 ms | 100 ms | How quickly compression releases after the signal drops below the threshold. Faster release = quicker recovery. Slower release = smoother, more natural sound. |
| Knee | 0-20 dB | 6 dB | Width of the transition zone around the threshold. 0 dB = hard knee (abrupt compression). Higher values = softer knee (gradual compression transition). |
| Output Gain | -12 to +24 dB | 0 dB | Make-up gain to compensate for volume reduction caused by compression. |
| Auto-Gain | On / Off | Off | Automatically calculates and applies make-up gain based on threshold and ratio settings. |
Understanding Key Parameters
Threshold
The threshold is where compression "kicks in." Set it so that:
- Peaks are compressed: Set threshold below your peak levels
- Gentle compression: Set threshold at or just below average signal level
- Heavy compression: Set threshold well below average level
Ratio
- 1:1 to 2:1: Subtle compression, glue, mix bus
- 3:1 to 6:1: General-purpose compression for vocals, bass, drums
- 8:1 to 20:1: Heavy compression, limiting, special effects
Attack Time
- Fast (0.1-5 ms): Controls transients tightly. Great for drums, limiting, peak control.
- Medium (5-30 ms): Balanced. Lets some transient through while controlling body.
- Slow (30-100 ms): Lets transients pass. Compresses the sustain. More natural on vocals and acoustic instruments.
Release Time
- Fast (10-50 ms): Quick recovery. Can add energy and pump. Risk of distortion on bass-heavy material.
- Medium (50-200 ms): Balanced, natural-sounding. Safe starting point.
- Slow (200-1000 ms): Smooth, gentle. Great for vocals, acoustic material, mastering.
Knee
- Hard Knee (0-3 dB): Obvious, defined compression. Good for effects and obvious control.
- Soft Knee (6-12 dB): More musical and transparent. Compression is less noticeable.
- Very Soft Knee (15-20 dB): Very gradual, gentle. Great for mastering and subtle control.
Auto-Gain Formula
When Auto-Gain is enabled, O-Comp calculates make-up gain using:
makeupGain_dB = -threshold × (1 - 1/ratio)This provides a reasonable starting point for compensating volume loss, though you may still want to fine-tune manually.
Tip: Use the gain reduction meter to aim for 3-6 dB of GR for natural compression, or 8-12 dB for more obvious effect.
Using the Compressor
Stereo Operation
O-Comp uses stereo-linked detection, meaning the detector analyzes the maximum of the left and right channels. This prevents stereo image shifting during compression — both channels receive identical gain reduction.
Zero-Latency Design
O-Comp introduces no lookahead delay, making it safe for:
- Live monitoring during tracking
- Real-time processing
- Parallel chains where latency alignment matters
Common Compression Tasks
Vocal Compression
- Threshold: -20 to -15 dB
- Ratio: 3:1 to 6:1
- Attack: 10-30 ms (let consonants through)
- Release: 100-300 ms (smooth, natural)
- Knee: 6-10 dB (gentle transition)
Drum Bus / Mix Glue
- Threshold: -10 to -5 dB
- Ratio: 2:1 to 4:1
- Attack: 5-15 ms (control peaks without killing punch)
- Release: 50-150 ms (rhythmic, energetic)
- Knee: 3-6 dB
Bass Guitar
- Threshold: -25 to -15 dB
- Ratio: 4:1 to 8:1
- Attack: 20-50 ms (preserve note attack)
- Release: 100-200 ms
- Knee: 6-10 dB
Master Bus
- Threshold: -6 to -3 dB
- Ratio: 1.5:1 to 3:1
- Attack: 10-30 ms
- Release: 200-500 ms (smooth, transparent)
- Knee: 10-15 dB (very soft)
Parallel Compression
For the "New York" compression technique:
- Send your source to a parallel bus/aux
- Insert O-Comp on the parallel bus
- Use aggressive settings (fast attack, high ratio, low threshold)
- Blend the heavily compressed signal with the dry signal
- Result: Consistent energy without squashing the original dynamics
Presets
O-Comp includes 8 factory presets covering common compression applications:
| Preset | Description |
|---|---|
| Gentle Glue | Subtle bus compression (2:1 ratio, soft knee) — adds cohesion without obvious compression |
| Vocal Smooth | Smooth vocal dynamics (4:1 ratio, medium attack/release, soft knee) — natural, transparent vocal control |
| Drum Punch | Fast attack/release for drums — controls peaks while adding energy and punch |
| Bass Control | Tame bass dynamics — consistent low-end without killing note attack |
| Mastering Touch | Light master bus glue (low ratio, very soft knee, slow release) — gentle final touch |
| Aggressive Smash | Heavy compression for parallel blending or special effects — obvious pump and energy |
| Natural Dynamics | Transparent control that preserves natural feel — gentle ratio with program-dependent release |
| Parallel Crush | Extreme settings for New York-style parallel compression — blend with dry signal for impact |
Managing Presets
Presets are stored at:
macOS: ~/Library/O-Comp/Presets/
You can create custom presets and share them by copying preset files to this directory.
Troubleshooting
Plugin Not Appearing in DAW
- Rescan your plugin directories in your DAW's preferences
- Verify the plugin is installed at the correct path (see Installation Paths above)
- On macOS, check that Gatekeeper hasn't blocked the plugin (System Settings → Security & Privacy)
- Restart your DAW after installation
No Compression / No Gain Reduction
- Lower the Threshold until it's below your signal peaks
- Check the input meter — ensure signal is reaching the compressor
- Increase the Ratio to make compression more obvious
- Watch the GR meter — it should show activity when signal exceeds threshold
Pumping / Breathing Artifacts
- Increase the Release time for smoother recovery
- Reduce the Ratio — less compression = less obvious artifacts
- Raise the Threshold so only peaks are compressed
- Increase the Knee for gentler compression onset
Too Squashed / Lifeless Sound
- Raise the Threshold to compress less of the signal
- Lower the Ratio (try 2:1 or 3:1 instead of 8:1)
- Increase Attack time to let transients through
- Use a softer Knee setting
Output Too Quiet After Compression
- Enable Auto-Gain for automatic make-up gain
- Manually raise Output Gain to match input level
- Aim to match the perceived loudness before and after compression
License Activation Issues
- Check your internet connection
- Verify the license key format is correct:
OUA-XXXX-XXXX-XXXX - Ensure you haven't exceeded the 3-machine activation limit
- Contact [email protected] if problems persist
High CPU Usage
- O-Comp is highly optimized and should use minimal CPU
- Check your DAW's buffer size settings — increase if needed
- Close other resource-intensive plugins