ZL Audio’s resonance suppressor plugin ZL Spectrum Equalizer is currently available as a free download.
In this article we cover the giveaway details and an overview of what ZL Spectrum Equalizer actually does.
What Is ZL Audio “ZL Spectrum Equalizer”?
ZL Spectrum Equalizer is a resonance suppressor that lets you pull down frequencies that stick out above everything else, pinpoint by pinpoint, while keeping the tone of the source intact. A high-performance FFT engine divides the incoming audio into individual frequency bins, and the gain of each bin is varied independently according to the level of the corresponding sidechain bin.
The developer officially describes it as a dynamic spectrum equalizer. Asked how it differs from the company’s own ZL Equalizer 2, they point out that ZL Equalizer 2 applies a wide filter curve based on a broadband trigger, whereas ZL Spectrum Equalizer uses FFT to operate directly in the frequency domain.
Key Features
- Spectral dynamic processing: an FFT engine splits the audio into individual frequency bins and moves the gain of every bin independently.
- The filter curve works as a processing range rather than a single band – every bin covered by the curve reacts on its own, so even a wide band is treated in fine detail.
- Three Dynamic Modes: Absolute (static threshold), Band (variable threshold that follows the sidechain loudness of the band) and Relative (variable threshold that follows the overall sidechain loudness).
- Adjustable smoothing type for the sidechain analysis – OCT (octave) or ERB (smoother in the low end) – plus a smoothing amount. Higher values make the processing smoother across the frequency axis.
- Threshold, attack, release and knee width can all be set for the per-bin processing.
- Frequency-dependent attack/release skew: raising the value makes the high end react faster and the low end slower.
- Spectrum gate: dynamic processing stays inactive whenever the sidechain loudness falls below the value you set.
- Seven spectrum resolution steps, from roughly 12 ms at Extreme Low to roughly 743 ms at Extreme High, so you can dial in the trade-off between frequency accuracy and latency.
- External sidechain input supported.
- Nine filter types (Peak / Low Shelf / Low Pass / High Shelf / High Pass / Notch / Band Pass / Tilt Shelf / Flat Tilt), five stereo modes (Stereo / Left / Right / Mid / Side), seven selectable slopes and up to 24 bands of linear-phase processing.
- Interactive spectrum graph with collision detection built into the interface.
How to Download and Install ZL Spectrum Equalizer
Downloading and installing is straightforward – just head to the “Installation” section on the official product page and follow the instructions there.
Summary
That covers the free giveaway of ZL Audio’s ZL Spectrum Equalizer. If harsh resonances in vocals, guitars or dense mixes are a regular problem for you, a bin-accurate dynamic spectrum EQ like this is a genuinely useful addition to your toolkit – and it costs nothing to try.