4K-EQ

4K-EQ is a professional SSL 4000 series console EQ emulation, bringing the legendary sound of classic British mixing consoles to your DAW — completely free.

Overview

The SSL 4000 series consoles are renowned for their musical, punchy EQ character. 4K-EQ captures that sound with accurate analog modeling, including the distinct characteristics of both E-series and G-series consoles.

Whether you’re tracking, mixing, or mastering, 4K-EQ delivers the SSL sound that has shaped countless hit records.

Brown vs Black Modes

4K-EQ faithfully recreates both SSL console variants:

Brown (E-Series)

• Musical, broader curves
• Gentle shelves with fixed Q
• Predominantly 2nd harmonic saturation (warm, transformer-colored)
• The classic “big console” sound

Black (G-Series)

• Surgical, tighter response
• Proportional Q (increases with gain)
• More 3rd harmonic saturation (clean, transformerless)
• Bell/Shelf switching on LF and HF bands

Saturation Modeling

4K-EQ includes multi-stage SSL-accurate saturation:

• Input transformer coloration
• NE5534 op-amp characteristics
• Output transformer harmonics (E-Series only)
• Per-band saturation when boosting

Clean by default (0% saturation) — SSL consoles are transparent unless driven. Push the Drive control to add warmth and glue.

Factory Presets

4K-EQ includes 15 professionally crafted presets:

Technical Specifications

DSP Details

• Filter topology: Biquad IIR with SSL-specific coefficient shaping
• Frequency warping: Pre-warped for HF accuracy (prevents digital cramping)
• Saturation model: Asymmetric soft-clipping (NE5534 op-amp characteristic)

Parameter Ranges (SSL Hardware-Accurate)

• LF Gain: ±20dB

  LF Freq: 30–480Hz

• LMF Gain: ±20dB

  LMF Freq: 200–2500Hz

• HMF Gain: ±20dB

  HMF Freq: 600–7000Hz

• HF Gain: ±20dB

  HF Freq: 1.5kHz–16kHz

• Q Range: 0.4–4.0 (proportional in Black mode)
• HPF: 16–350Hz (18dB/oct)
• LPF: 3kHz–22kHz (12dB/oct)
• Saturation: 0–100%
• Output Gain: ±12dB

Performance

• CPU usage: ~1–2% per instance (2x oversampling, 48kHz)
• Memory: ~10MB per instance
• Latency: ~32 samples (2x) / ~96 samples (4x)
• Highly optimized — use on every channel without CPU issues

DAW Compatibility

Fully Tested

• Reaper — VST3/LV2, all features working
• Ardour — LV2 with full GUI
• Carla — VST3/LV2, standalone host
• Standalone — JUCE standalone application

Expected to Work

• Bitwig Studio, Studio One, FL Studio
• Ableton Live, Cubase/Nuendo
• Logic Pro, GarageBand (AU on macOS)

Installation

Linux

VST3: ~/.vst3/4K EQ.vst3
LV2:  ~/.lv2/4K EQ.lv2

Windows

VST3: C:\Program Files\Common Files\VST3\4K EQ.vst3

macOS

VST3: ~/Library/Audio/Plug-Ins/VST3/4K EQ.vst3
AU:   ~/Library/Audio/Plug-Ins/Components/4K EQ.component

Open Source

4K-EQ is open source under GPL-2.0. View the source, report issues, or contribute on GitHub.

Disclaimer: This is an independent emulation inspired by SSL 4000 series consoles. SSL and Solid State Logic are trademarks of Solid State Logic Ltd. This project is not affiliated with or endorsed by SSL.