The Main Squeeze User Guide

The Main Squeeze is a mastering bus compressor built to make a mix feel less like separate tracks and more like music. It is about cohesion: controlling dynamics while preserving the scale, impact, and emotional movement of the record.

It is not an emulation of another compressor, and it is not designed as an all-purpose processor with endless topologies. Its controls are deliberately focused: decide how much compression is needed, how the compressor should recover, and how much of that movement belongs in the finished master.

Use it on the full mix bus when you want the record to move together. In a mastering chain, it can sit before or after EQ depending on whether you want tonal shaping to influence its response. That is a workflow choice, not a fixed rule.

Quick Start

Start with Contour set to Transparent.
Lower Threshold until the gain-reduction meter shows controlled, intentional movement.
Set Attack and Release to preserve the pulse and transient shape of the track.
Try Cohesive if you want the release to follow the program more naturally, or Deep for more sustained connection.
Use Makeup and Mix to compare fairly. Match perceived level before deciding that more compression sounds better.
Create an alternative in A/B, then use Bypass for the final reality check.

The Core Controls

Threshold and Ratio

Threshold sets the level where soft-knee gain reduction begins. Lower it for more compression; raise it for less.

Ratio determines how firmly compression is applied once the signal crosses Threshold. Lower ratios can provide subtle control. Higher ratios make the compressor hold the material more decisively.

Use these together. Do not choose a ratio by category or habit — listen for the amount of movement that keeps the mix connected without making it smaller.

Attack and Release

Attack controls how quickly the compressor responds. A faster setting catches more of the transient; a slower setting lets more of the initial impact through.

Release controls how quickly gain returns after compression. It is the foundation for how the record breathes — and the control that Contour reshapes.

The available ranges are:

Threshold: −48 to 0 dB
Ratio: 1.0:1 to 20.0:1
Attack: 0.1 to 300 ms
Release: 10 to 1,000 ms

Start by matching the release to the musical movement. If the compressor recovers too quickly, the record can become restless or brittle; too slowly, and it can stay held down after the moment has passed.

Contour

Contour is the central character control in The Main Squeeze. It does not add saturation, analogue colour, or a different compression curve. Threshold, Ratio, Attack, Makeup, and Mix behave consistently across all three choices. Contour changes the way the compressor recovers.

Transparent

Transparent uses the Release time exactly as you set it. Choose it when you want a familiar, direct mastering compressor response: predictable timing, clean control, and no additional program dependence.

Cohesive

Cohesive makes recovery more responsive to the program. Sustained passages make the compressor hold a little longer and release more gradually, helping the mix move as one connected system rather than recovering independently from every hit.

An isolated transient still recovers close to the Release time you chose. The effect becomes more apparent when the material has sustained density or repeated energy.

Deep

Deep takes the Cohesive idea further. It engages sooner, holds longer, and creates more persistent long-term movement. Use it when you want density and connection without turning the compressor into a different kind of effect.

Think of Deep as more of the same contour — not a separate sonic personality. If it starts to make the record feel smaller, less is usually the better choice.

Level and Parallel Compression

Makeup

Makeup is manual output gain after compression. Use it to recover level lost to gain reduction and to make comparisons fair. There is no automatic makeup or gain-match system, so take a moment to match perceived level yourself.

Makeup ranges from −24 to +24 dB.

Mix

Mix blends the uncompressed signal with the compressed signal after Makeup gain. At 100%, you hear fully processed audio. Lower settings create parallel compression: the compressor can supply density and control underneath while more of the original transient shape remains.

Use Mix as a musical control, not a rescue button. If the compressed sound only works when it is mostly hidden, reconsider Threshold, Ratio, Attack, Release, or Contour first.

Gain Reduction

The gain-reduction meter shows how much the stereo-linked compressor is currently working, from 0 to 24 dB. The needle rests at 0 and moves right as reduction increases.

It is there to provide context, not a target. A small amount of gain reduction can be transformative; more can be right when the music calls for it. Listen for the relationship between impact, density, and motion rather than chasing a number.

Sidechain HPF

The Sidechain HPF changes what the compressor listens to, not the audio you hear. When enabled, frequencies below the selected cutoff have less influence over gain reduction.

Use it when kick, bass, or sub energy is causing more compression than the perceived loudness of the full mix warrants. It can keep the low end present while preventing it from making the rest of the record pump unnecessarily.

The Sidechain HPF is off by default and is adjustable from 20 to 500 Hz. It is an internal detector filter, not an external sidechain input.

Comparison and Workflow

A/B

A/B stores two complete Main Squeeze states. Use it to compare two real compressor decisions — perhaps Transparent versus Cohesive, or a slower attack versus a faster one — without rebuilding your settings.

Match levels between A and B before deciding. Different makeup gain or different Mix settings can otherwise make the louder state seem better.

Presets, Undo, and Redo

The preset strip provides factory and user presets. Save your own starting points with Save As…; user presets can be renamed or deleted.

Undo and Redo track normal editing gestures and preset recall. A/B is intentionally a separate comparison system: switching slots restores the complete state but clears the current Undo history.

Bypass

Bypass passes the signal through completely unprocessed. It crossfades smoothly, so you can compare without clicks. Return to Bypass often, but always compare at a matched level.

Practical Workflows

Transparent control

Choose Transparent when you need clear, predictable dynamics control. Start with a moderate ratio, let Attack preserve enough transient shape, and tune Release to the rhythm of the track.

Cohesive glue

Choose Cohesive when the mix feels like it needs to settle into a shared movement. Let the program-dependent release do the subtle work; avoid forcing it with excessive Threshold or Makeup.

Deeper movement

Choose Deep when a denser or more sustained connection is part of the aesthetic. It can be powerful on material that benefits from a stronger long-term hold, but small changes go a long way.

Keep the low end from steering everything

Engage the Sidechain HPF when sub or kick energy is dominating the detector. Raise the frequency only as far as necessary. The aim is not to remove bass from the record — it is to stop low-frequency peaks from making the compressor overreact.

Final decision

Build two candidates in A and B, level-match them with Makeup and Mix, then step away briefly. When you return, the right setting should make the record feel more connected without announcing the compressor.

Updates, Licensing, and Support

The Main Squeeze is available as AU and VST3 for macOS. The About overlay shows the installed version, provides access to this User Guide and the Mainline Audio site, and lets you enable or disable tooltips.

For current downloads, release notes, and support, visit the product page or support@mainline-audio.com.

Final Perspective

The goal of The Main Squeeze is not compression for its own sake. It is the moment when a record starts to feel like one piece of music. Keep the decisions deliberate, compare at matched levels, and stop when the connection is felt more than heard.