Manual

How to use ZL Compressor

About

ZL Compressor is a dynamic range compressor with the following key features:

  • Four Versatile Compression Styles: Choose from four distinct modes. Clean offers a transparent, modern VCA design. Classic delivers the character of a feedback FET compressor. Optical provides smooth, warm leveling inspired by light-sensitive circuits. Vocal is specifically tailored to enhance and control vocal tracks.
  • Advanced Side-chain Control: Utilize the full 8-band Equalizer to make the compressor react to specific frequencies. Fine-tune the stereo image with an adjustable stereo link. Catch the fastest transients with predictive lookahead.
  • Pristine Audio Performance: Eliminate aliasing artifacts with up to 8x oversampling, ensuring pure sound even at extreme settings. The CPU-efficient algorithm lets you run multiple instances without overloading your project.
  • Intuitive Visual Interface: Instantly see your audio’s dynamics on the large Peak/RMS analyzer and adjust the side-chain directly on the interactive spectrum display. This clear visual feedback helps you make better mixing decisions, faster.

Top Panel

Work in progress.

Oversample

There are four over-sampling options:

  • OFF: No over-sampling. No extra latency.
  • 2x: 2 times over-sampling. 64 sample latency (~ 1.3 ms under 48kHz)
  • 4x: 4 times over-sampling. 72 sample latency (~ 1.5 ms under 48kHz)
  • 8x: 8 times over-sampling. 76 sample latency (~ 1.6 ms under 48kHz)

You may hear clicks/pops when you change this parameter. Please DO NOT automate this parameter.

Lookahead

The delay of the main-chain signal. When PDC is supported (in almost all DAWs), it can be interpreted as the lookahead time of the side-chain signal.

You may hear clicks/pops when you change this parameter. Please DO NOT automate this parameter.

Left Side Panel

  • Press: open the side-chain equalizer
  • Release: close the side-chain equalizer

  • Press: open the side-chain panel
  • Release: close the side-chain panel

Center Panel

The center panel consists of a magnitude analyzer, a cumulative RMS analyzer and a computer display.

Magnitude Analyzer

The magnitude analyzer occupies the whole center panel. It shows three curves:

  • the pre curve: magnitude of the input main-chain signal
  • the post curve: magnitude of the output main-chain signal
  • the reduction curve: magnitude of the gain reduction

In the bottom-left corner, you can select the analyzer’s time window length (6 s, 9 s, 12 s, and 18 s). To ensure visual fluidity, the 6 s and 9 s settings perform best with a refresh rate of 60 Hz or higher.

In the bottom-right corner, you can select the magnitude type (Peak and RMS) and the minimum decibel value of the analyzer (-9, -18, -36, -54, and -72).

Cumulative Analyzer

The cumulative analyzer on the left shows the cumulative RMS values of the input main-chain signal and the output main-chain signal. You can double-click to reset this analyzer.

Computer Display

The computer display shows the curve that is used to calculate the gain reduction value.

Bottom Panel

Knee

Controls the knee width of the gain reduction computer. A wider knee makes the transition between the uncompressed state and the compressed state smoother.

Curve

Controls the non-linearity behavior of compressed state.

Threshold

Ratio

Compression Style

  • Clean: feedforward design with exponential decayed attack/release stages, which offers transparent, precise dynamic control.
  • Classic: feedback design with exponential decayed attack/release stages, which offers smooth, glued dynamic control
  • Optical: feedforward design with linear decayed attack/release, which offers smooth, precise dynamic control
  • Vocal: feedback design with linear decayed attack/release, which offers gentle, buttery dynamic control

Pump

Controls the behavior of the attack stage. Larger Pump makes the attack more aggressive, which introduces the pumping effect.

Smooth

Controls the behavior of the release stage. Larger Smooth makes the start of the release stage slower.

Attack

Release

Range

Controls the gain reduction range. The actual value is affected by the Wet.

Hold

Controls the minimum amount of time where gain reduction is prevented from decreasing. During this time, compression can react to new peaks but cannot release.

Makeup

Controls the makeup gain that is applied after the compression. The actual value is affected by the Wet.

Wet

Controls the percent of wet signal.

Side-chain Panel

Set the stereo mode to Mid/Side.

Set the stereo mode to Left/Right.

  • Press: swap the side-chain stereo mode
    • if the stereo mode is Left/Right, the side-chain is from Right/Left
    • if the stereo mode is Mid/Side, the side-chain is from Side/Mid

Stereo Wet

Controls the percent of wet signal for each stereo channel. The actual value is affected by the Wet.

Gain

Controls the gain of the side-chain signal.

  • Press: use external side-chain signal
  • Release: use internal side-chain signal

  • Press: listen to the side-chain signal

Side-chain Equalizer

The side-chain equalizer allows you to visually equalize the side-chain signal. It features a spectrum graph where you can add and manipulate filter bands.

Add a Band

If there is at least one frequency band in the off state when you double-click the spectrum, a frequency band will be turned on with the corresponding frequency/gain:

  • Frequency < 20Hz: Adds a High Pass filter.
  • 20Hz <= Frequency < 50Hz: Adds a Low Shelf filter.
  • 50Hz <= Frequency < 5000Hz: Adds a Peak filter.
  • 5000Hz <= Frequency < 15000Hz: Adds a High Shelf filter.
  • 15000Hz <= Frequency: Adds a Low Pass filter.

Drag a Band

When a frequency band is not in the off state, a draggable button appears at the corresponding frequency/gain position. You can adjust the frequency and gain by dragging the button, and adjust the Q value with your mouse wheel.

When you select the frequency band via clicking the button:

  • an additional control window will appear near the button, through which you can quickly bypass/close the selected band, choose the filter type, and adjust the filter slope.
  • the frequency/gain values will appear at the top-left corner, through which you can view/edit the frequency/gain values of the selected band