SMOOTH by KERN Audio dynamics plugin interface with spectral display

SMOOTH: Dynamic Resonance Suppressor Plugin by KERN Audio

SMOOTH is a dynamics processor plugin by KERN Audio that reduces resonances across 40 ERB bands, acting on each band only when a resonance flares. It is available in VST3 and AU formats for Windows and macOS.

VST3AUWindowsmacOS64-bit

AVAILABLE ATPlugin Boutique

Download Now

Opens the store in a new tab

01Overview

SMOOTH is built around dynamic suppression rather than static equalization. Its 40 bands are spaced to follow how the ear resolves frequency, so each band responds on its own. Resonance mode targets sustained harshness, while transient mode addresses percussive spikes, and you can switch between them or blend the two. A 4096-point FFT drives a real-time spectral display that shows which frequencies are being reduced. The developer also describes the plugin as running with under 3% CPU usage.

Best for

Vocal resonance control
Harsh mix correction
Mid-side vocal taming
Transient spike reduction
Mastering resonance cleanup

Developer: KERN Audio
Category: Dynamics Processors
Store: Plugin Boutique

02Key features

What you get

40 ERB bands mapped to human frequency perception
Resonance mode for sustained harshness
Transient mode for percussive spikes
Switchable or blendable character modes
M/S processing for independent mid and side control
Real-time spectral display of reduced frequencies
4096-point FFT analysis
Zero-delay feedback filters
Five controls and 32 factory presets

03In depth

Psychoacoustic Band Design and Dual Modes

SMOOTH divides the spectrum into 40 ERB bands, a split based on how the ear resolves frequency rather than evenly spaced or arbitrary divisions. Each band is processed independently, so the plugin only acts where a resonance rises above its threshold.

The two character modes cover different problems. Resonance mode is aimed at sustained harshness that lingers in a sound. Transient mode handles percussive spikes that come and go quickly. You can choose one mode or blend them to match the material.

The real-time spectral display shows the frequencies being reduced, so you can see what the processor is responding to as you adjust it.

M/S Routing and Workflow

SMOOTH includes M/S processing, which lets you treat the mid and side channels separately. KERN Audio points to this for taming center-panned vocals without affecting the stereo field. Five controls keep the interface compact, and 32 factory presets give you starting points to adjust.

The plugin uses zero-delay feedback filters, and the developer lists it as available in VST3 and AU formats on Windows and macOS.

04Specs

Will it run?

Formats, systems and requirements as listed by Plugin Boutique. Missing details are left out, not guessed.

Developer	KERN Audio
Type	Plugin
Category	Dynamics Processor
Formats	VST3, AU
Operating systems	Windows, macOS
Architecture	64-bit

05FAQ

Questions, answered

What formats does SMOOTH support?

SMOOTH is available in VST3 and AU formats. It runs on Windows 10+ and macOS 10.13+, including Intel and Apple Silicon Macs.

What do I need to use SMOOTH?

SMOOTH needs a 64-bit DAW or any VST3 or AU compatible host. Windows users need Windows 10 or later, and Mac users need macOS 10.13 or later.

What is the difference between Resonance and Transient mode?

Resonance mode targets sustained harshness, while Transient mode targets percussive spikes. You can switch between the two or blend them.

Can SMOOTH process vocals without changing the stereo width?

Yes. The M/S routing lets you process the mid and side channels independently, which KERN Audio describes as a way to tame center-panned vocals without touching the stereo field.