Level: a 2A-style opto leveller
Module 05 of 14 · Optical compressor (2A-style)
- One Move knobPeak reduction
- Latency0 ms
- CPU, iPad Air M31.3 %
- Default position5 of 14, before Punch
Level is a 2A-style optical compressor. It evens out a vocal smoothly and slowly, so it sounds levelled rather than squashed. One knob sets how much. It was modelled on the published behaviour of the classic opto circuit and fitted to measured reference curves.
Hear it
Level into Punch
The 2A-style opto leveller driving the 76-style FET limiter at 8:1: a heavy, obviously compressed sound with the quiet lines pulled up. Before and after are set to the same loudness, so you hear the change, not a level jump.
"More Than 2 Sides (accapella)" by Colin Mutchler (ccmixter.org/files/commonsplice/2599), licensed CC BY 2.5 (creativecommons.org/licenses/by/2.5). Excerpt, processed by OneMove Vocal Console.
Level and CLA-2A
The same take through Level (Smooth & Heavy) and CLA-2A (Vox preset). Before and after are set to the same loudness, so you hear the change, not a level jump.
"More Than 2 Sides (accapella)" by Colin Mutchler (ccmixter.org/files/commonsplice/2599), licensed CC BY 2.5 (creativecommons.org/licenses/by/2.5). Excerpt, processed by OneMove Vocal Console. Compared with Waves CLA-2A, Vox preset.
The One Move: Peak reduction
The knob covers the useful range of Peak Reduction, from no levelling at 0 to about 15 dB of levelling on a vocal at −18 dBFS at the top. Auto Gain matches the loudness as you turn it, so you hear the levelling, not a level change. The threshold follows the voice's own level, so the knob means the same on a quiet singer and a loud one.
Expert
| control | what it does |
|---|---|
| Peak Reduction | how hard the voice drives the optical cell |
| Gain | make-up gain, −12 to +24 dB (Auto Gain sets it for you) |
| Compress / Limit | a gentle ratio, or a firmer one |
| HF Emphasis | bright, sibilant parts push the levelling harder |
| Memory | after long, heavy levelling the release gets slower, as an optical cell does |
| Colour | the valve stage's harmonics, 0–200 % |
| Air Lift | opens the very top as the levelling deepens |
| Mix | blends the dry voice back in |
How it behaves. An optical cell answers along a curve: about half the gain comes back in tens of milliseconds and the rest over seconds; the first milliseconds of a word get through before the voice is levelled; and the ratio rises gradually. Level models each of these. Detector guards keep plosives and sibilance from slamming it.
The ⇄ key between Level and Punch swaps their order: the default levels first, then lets the FET add bite.
Specs
| Static curves vs measured reference (1 kHz, −40 to 0 dBFS) | within 0.25–0.38 dB RMS |
| Release, half recovery | 160 ms (reference 170 ms) |
| Latency | 0 ms (no look-ahead) |
| CPU, iPad Air M3, only Level on | 1.3 % of one core |
Method: Level and Punch: an opto leveller and a FET limiter, measured.
FAQ
Is this an LA-2A emulation?
It is a 2A-style opto leveller: our own design, written from an analysis of how the classic optical circuit behaves and fitted to measured curves. It is not a copy of any product and has no affiliation with its maker. LA-2A is a trademark of Universal Audio, Inc.
Should Level go before or after Punch?
Both work. Level first gives a smooth, even voice that Punch then sharpens. Punch first catches the peaks so Level can level gently. Try both with the ⇄ key.