Stemwire’s Levelproof Compressor Keeps Loudness Constant
Stemwire Releases Levelproof Compressor with Auto Loudness Matching
Stemwire has released Levelproof Compressor, a new effect plugin for macOS and Windows. It aims to solve a common problem: compression changes loudness, which makes A/B testing unreliable. The plugin measures the loudness difference and applies automatic makeup gain. Therefore, every setting lands at the same loudness. Consequently, you can compare settings purely on their sonic character.
How It Measures Loudness
Levelproof uses the K-weighting and BS.1770 gating standard. It compares the loudness of the input signal with the compressed output. The difference becomes the makeup gain. After each parameter change, the plugin re-measures the match and holds it until the next adjustment. A manual Learn option is also available. In addition, a short replay of recent audio predicts the new match immediately, then the measurement takes over. As a result, gain staging takes care of itself while you work.
Another advantage is that offline rendering is serviced on the render thread. Therefore, a bounce and playback agree with each other. The plugin also exports match playback at any render speed.
Four Compression Models
The plugin includes four models: CLASSIC, BUS, BUTTER, and PUNCH. Each handles gain reduction in its own way. For instance, CLASSIC offers restrained levelling, while PUNCH provides harder transient control. BUS works well on groups, and BUTTER adds a smooth character. Despite their differences, all four arrive at the same loudness. That means switching mid-listen is a straight comparison of behaviour. Even the bypass sits at that same level. Thus, you can finally trust your ears during A/B tests.
Controls and Integration
You get threshold, ratio, attack, release, mix, and output controls. Additionally, there are detector-only sidechain high-pass and low-pass filters on every model. The Levelproof matching includes a lock function to hold the current match. You can also trigger a manual relearn. Presets and full state saving are included. Attack and release are real milliseconds, converted at the active sample rate.
Pricing and Demo
Levelproof Compressor costs $29.00. A free demo is available with no time limit. The demo includes the full plugin, every model, presets, and state saving. The only limitation is occasional noise bursts. There is no trial countdown and no recurring network check. The macOS version is universal, signed, and notarized, with VST3 and Audio Unit formats. The Windows version is x64 and offers VST3.
Features
- Automatic makeup gain based on measured LUFS difference
- Four compression models: CLASSIC, BUS, BUTTER, PUNCH
- Sidechain high-pass and low-pass filters
- Real milliseconds attack and release
- Lock and manual relearn for loudness matching
- Presets and full state saving
- Free unlimited demo with occasional noise bursts
Price
$29.00 (USD)
Pros
- Every setting lands at the same loudness, enabling reliable A/B testing
- Four distinct compressor models with real milliseconds attack and release
- Free unlimited demo with no time limit and no recurring network check
Cons
- Demo version adds occasional noise bursts
- Only available as VST3 and AU, no AAX support
More info: Stemwire | Levelproof Compressor
