Skip to content

SOL-4 Mastering Limiter

New Release Free Trial Download

SOL Studio Audio  /  Mastering Tools

SOL-4 — Transparent Limiter
with No Hidden Behavior

“Uncompromisingly clean — but it never strips away the harmonics your music needs.”

A professional mastering limiter that shows you exactly what it’s doing, sounds exactly as neutral as you want it to, and gets out of the way.

Buy Now — $39.90

Intro price  $39.90   Regular $69.90

VST3 Windows 10 / 11 64-bit   Mac coming soon

Oversampling

8x

Maximum quality mode

Latency

0 ms

Zero-latency capable

Processing

M/S

Full mid/side domain

LUFS

BS.1770

M / S / I metering

True Peak

3-phase

8-tap FIR interpolator

Presets

13

Factory + user saves

Core Design

Built for mastering engineers who trust their ears.

Every parameter in SOL-4 does exactly what it says. No secret sauce, no hidden saturation. Just transparent, precise gain control.

Zero Latency Mode

Disable lookahead and oversampling for completely latency-free operation. Perfect for live monitoring, real-time adjustments, and CPU-critical sessions.

Spectral-Dependent Release & Crossover Solo

Separate release multipliers for low and high frequency bands, divided by an adjustable crossover frequency. Enable Crossover Solo to audition the low band in isolation — useful for setting the crossover point by ear.

M/S Domain Processing

All limiting happens in Mid/Side space. The S-Floor Link parameter gives continuous control over stereo width preservation — from fully independent to fully linked.

Delta Monitoring

Hear exactly what the limiter is removing. Complete silence means no gain reduction. Audible content tells you precisely how hard the limiter is working — and what it costs.

Transient Preservation

Protect the initial attack of transients without allowing peaks to exceed the ceiling. Drums and percussion stay impactful, even at high gain reduction.

Auto Release Modulation

Automatically extends release time during dense passages to prevent inter-modulation distortion, then shortens during sparse material. Fully adjustable.

True Peak Limiting

A 3-phase, 8-tap FIR interpolator detects inter-sample peaks. Combined with micro soft-clip at the ceiling, SOL-4 delivers robust true peak compliance at any oversampling setting.

Detector Weighting

Four K-weighting modes determine how aggressively the limiter responds to high-frequency content. From subtle (0.25) for acoustic material to flat (FLAT) for drum-heavy tracks.

A/B Comparison + Undo

Two independent parameter slots for instant side-by-side comparison. Full undo/redo history. Non-destructive workflow at every step.

Dithering & Noise Shaping

Built-in TPDF dithering for 16-bit and 24-bit output, with four noise shaping curves (FLAT, HF1, HF2, HF3). SOL-4 handles the complete final delivery chain — limiting, true peak control, and word-length reduction in a single plugin.

Resizable Interface

The plugin window scales freely to fit your workflow — from compact on a crowded screen to large for detailed metering and GR history inspection. Two color themes: SILV (default, cool silver) and GOLD (warm gold) — switchable at any time to suit your studio environment.

Metering Suite

Everything you need to see. Nothing you don’t.

SOL-4’s metering gives you immediate, accurate feedback on what’s happening.

BS.1770-4 LUFS — M / S / I

Full loudness metering: Momentary (400 ms), Short-term (3 s), and Integrated with -70 LUFS absolute gate. All three values displayed simultaneously in real time. Click to reset.

GR History Graph

Scrolling gain reduction history for Mid and Side channels. Three scroll speeds (SLOW / MED / FAST) let you zoom from full-song overview to individual transient detail.

Knee Curve Display

Live input/output transfer curve. The full knee width is always visible regardless of the KNEE setting — readable from 0 to 12 dB.

MID / SIDE Solo + Output Meters

Audition Mid or Side channels independently. Peak-hold output meters for Left and Right with True Peak display and ballistic LED-style response.

Pricing

SOL-4 Mastering Limiter

Intro Price

$39.90

Regular price: $69.90

  • —  SOL-4 VST3 plug-in (Windows 64-bit)
  • —  PDF User Manual
  • —  13 factory presets
  • —  Free updates within version 2.x
  • —  Support via info@solstudio.online
Purchase on Gumroad

Requires Windows 10 or 11 (64-bit). Mac version in development.
No subscription. No iLok. No internet connection required after purchase.