Research Notes: Pressure
Last updated: 2026-05-26 · Plugin v1.6.0
Current Test Status
- ✓Survived The Gauntlet™ (1,000,000 parameter mutations, 0 crashes)
- ✓Category 5 stress tests passing
- ✓Zero audio artifacts detected in stress testing
- ✓Pluginval clean (strictness 10)
- ✓Zero memory leaks over 1 hour marathon test
Validation Depth
801
Total Tests
ASan · UBSan · TSan · RTSan
Sanitizer Lanes
10
Pluginval Strictness
Production latency: ~85 µs/block on M4 Pro at 48.0 kHz / 512 samples
Audio Quality Specs
Measured at −12 dBFS, 60% pressure
| Engine | THD Range | Character |
|---|---|---|
| MIX (VCA) | 0.02–0.06% | Clean bus control |
| INST (FET) | 0.05–3.0% | Fast, assertive control |
| VOCALS (Opto) | 0.4–0.7% | Smooth vocal-focused leveling |
| DRUMS (VCA) | 0.01–0.08% | Transparent dynamics |
| MASTER (VariMu) | 0.06–1.9% | Wide-knee density control |
Swipe sideways to compare
Engine Response Characterization
Measured 2026-05-31. Controlled lower-layer characterization at approximately 6 dB raw gain reduction.
These measurements are response fingerprints, not universal quality rankings or release thresholds. They do not claim preset, AUTO-mode, lookahead, oversampling, or full-plugin behavior.
| Mode | Voice | Time to 90% engagement | Recovery to 10% | Observed tail shape |
|---|---|---|---|---|
| MIX | Clean bus control | 12.0 ms | 481 ms | Multi-stage observed |
| INST | Fast assertive control | 0.1 ms | 534 ms | No multi-stage flag |
| VOCALS | Smooth vocal-focused leveling | 11.8 ms | 5,704 ms | Multi-stage observed |
| DRUMS | Transient-conscious control | 20.3 ms | 593 ms | No multi-stage flag |
| MASTER | Wide-knee density control | 2.8 ms | 338 ms | No multi-stage flag |
Swipe sideways to compare
VOCALS: The final 1% recovery crossing remained above the measurement floor after the 20 s observation window.
What AUTO Does
AUTO is an engine-aware compression system. PRESSURE drives a tailored curve for the selected voice rather than applying one generic compressor setting.
- •Coordinates threshold, ratio, attack, release, and knee through per-voice curves.
- •Adds an input-aware threshold adjustment while preserving the selected voice's identity.
- •Uses TONE to shape engine-specific detector emphasis.
- •Keeps DRUMS-specific program-dependent release distinct from the shared AUTO curve system.
Internal characterization confirms that AUTO produces materially different behavior by voice and event duration. The published response table above remains the cleaner controlled comparison because it measures all five voices at approximately 6 dB raw gain reduction.
AUTO is not a universal material-adaptive attack/release algorithm, and these observations are not a five-engine AUTO timing table.
Framework Improvements
Issues identified through mutation testing and their resolutions.
- ✓
DC offset detection added to buffer validation
Mutation testing revealed that buffer validation did not yet cover DC offset. Detection was added with a −60 dBFS threshold, and all plugins were re-validated.
Resolved 2026-02-01
- ℹ
Sample-level discontinuity detection added
Mutation testing identified that the framework lacked sample-by-sample gradient analysis. A discontinuity detector with a 6 dB inter-sample threshold is being integrated to extend coverage to transient-level anomalies.
In progress
Why Public Research Notes?
Mutation testing is how we verify the test suite itself. By intentionally injecting faults into the plugin, we identify where the testing framework needs to improve—and then we improve it.
This page documents that cycle: what we found, what we fixed, and how the framework got stronger. Engineering rigor, documented in the open.
If you encounter unexpected behavior our tests haven't covered, we want to hear about it.
Learn more about our testing methodology: Testing Suite Documentation
Found a Bug?
If you crash it or hear artifacts our tests missed, email me:
keith@bellweatherstudios.comInclude: DAW + OS version, what you did before it crashed, crash log if available. Best bug reports get credited in release notes.