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Polarity Glue: Free SSL-Style Bus Compressor Plugin

Tutorial | Sep 13, 2026

Polarity Glue is a free SSL-inspired feedback bus compressor for Windows, macOS, and Linux, with Auto Makeup, parallel mix, waveform history, sidechain control, and output clipping.

Quick Answer

Short Overview

Polarity Glue is a free SSL-inspired feedback bus compressor designed for subtle mix bus and drum bus compression. Like the classic glue-compressor workflow, it helps tame peaks and gently bind multiple sounds together without adding overly aggressive punch, making it useful on buses and full mixes where cohesion matters more than heavy character.

The plugin extends that familiar design with practical modern features such as auto gain compensation, output peak clipping, sidechain filtering, external sidechain support, oversampling options, and visual gain-reduction history. For producers working across Windows, macOS, and Linux, it offers a lightweight, no-subscription solution for transparent bus compression and controlled parallel processing.

Key Takeaways

Polarity Glue: a Free SSL-Style Bus Compressor for Windows, Mac, and Linux

Polarity Glue is an independent bus compressor inspired by the sound and working style associated with classic SSL feedback compression. It covers the familiar glue-compressor workflow without claiming an identical circuit, sound, or null match to Ableton Glue, Cytomic The Glue, or any hardware unit.

It is meant for gentle, musical dynamics control rather than aggressive transient shaping. Instead of making drums hit harder or sound more smashed, it is intended to help multiple sounds feel more cohesive when routed through a shared bus or the master channel.

What It Does

Polarity Glue is best used on:

In this context, “glue” refers to light compression that smooths level differences and makes separate elements feel more unified. This style of compressor is typically used to tame peaks gradually rather than produce obvious pumping or heavy coloration.

How It Works

The plug-in uses a feedback bus-compression design associated with SSL-style compressors. It includes familiar visual and functional elements from that category, including:

The history meter provides a visual indication of when compression begins and how strongly it responds. That makes it easier to dial in settings by ear and sight together, especially on buses and full mixes.

Auto Gain for Easier Comparison

One of the key workflow features is automatic gain compensation.

Auto Makeup compares energy before and after gain reduction. After a relevant compressor change, it waits 300 ms for stable settings, measures two seconds of active audio, transfers the result smoothly, and then stops analyzing. The held result is compensation for measured energy loss, not continuous gain riding or a perceptual loudness guarantee.

This has two practical benefits:

A manual make-up gain option is also available for users who prefer direct control instead of automatic compensation.

Peak Clipper at the Output

Polarity Glue includes a peak clipper on the output stage.

When enabled, the internal soft clipper shapes peaks before a final -0.1 dBFS sample-peak guard catches downsampling overshoot. A clip indicator shows when clipping occurs. This final guard has no lookahead and is not a true-peak guarantee.

This can be useful when compression and gain compensation push the signal toward clipping.

Sidechain Controls

The plug-in supports external sidechain input, allowing one signal to control compression on another. Depending on the host, a separate track, instrument, or bus can be selected as the sidechain source.

It also includes a sidechain high-pass filter. This lets low-frequency content be reduced in the detector path so that large bass events or kick drums do not trigger excessive gain reduction. In practice, this can help preserve stability and avoid overreaction to low-end energy.

Range and Parallel Mix

Range limits the detector target inside the feedback loop, so it affects both the depth and recovery of compression rather than merely limiting the displayed gain reduction. The Mix control blends phase-matched dry and wet paths for parallel compression without requiring a second track.

Workflow Features

Additional workflow features include:

The oversampling controls allow lower or moderate CPU use during playback while still using higher oversampling during export if desired.

Practical Uses

Drum bus glue

A typical use case is placing the compressor on a drum bus and applying light gain reduction so the kick, snare, hats, and percussion feel more connected without becoming overly aggressive.

Master bus smoothing

On the master, the compressor can be used carefully to shave peaks and add subtle cohesion across the whole mix. Heavy settings are possible, but they are presented more as demonstrations of the controls than recommended mastering practice.

Parallel compression

Because of the auto gain and mix control, it is easy to blend compressed and dry signal for parallel compression without the level mismatch that often makes louder settings seem automatically better.

Platform Support

Polarity Glue is available as:

Linux support is included, though compatibility can be more complex because distributions, desktop environments, and window managers differ.

Limits and Current State

This is an early release, so interface details and host-specific behavior may still be refined. Users can save and share their own local presets, but there is no bundled factory-preset library yet.

Philosophy Behind the Release

The plug-in is offered free of charge with no subscription, iLok, serial-number requirement, telemetry, or mandatory email submission. The project is positioned as part of a broader effort to provide native tools that work across operating systems, including Linux, while keeping the feature set practical and user-focused.

Availability

Polarity Glue is available from the dedicated download page for Windows, macOS, and Linux.

Video Chapters

Transcript

This is the transcript of the video. The text was generated automatically and may contain small mistakes. The timestamps jump to the matching part of the video.

Click to expand transcript

[00:00:00] Okay, today I want to show you a new free plug-in called Polarity Glue.
[00:00:06] And if you know the Ableton Glue Compressor or the Glue VST plug-in, this is more or less
[00:00:11] the same thing.
[00:00:12] So it's a very gentle SSL style feedback bus compressor.
[00:00:17] So it's not a compressor for making your drums more aggressive or anything like this.
[00:00:23] You really have to put it on a bus with multiple sounds, let's say the drum bus here, where
[00:00:28] you have the kick drum, snare drum, the hi-hats and so on, and you want to glue these sounds
[00:00:33] together.
[00:00:34] Or you put it on the master.
[00:00:35] I have it in the master here, multiple sounds in there, actually all of the sounds of the
[00:00:40] track, and then you try to slowly tame some of the peaks with that.
[00:00:46] I also added to this plug-in some features I really like to see in most of my dynamic
[00:00:52] plug-ins, for instance here, the peak clipper at the output stage, so it clips here at the
[00:00:58] moment at 0 dB.
[00:01:00] And you can also see that it's clipping here with this clip label at the right side.
[00:01:05] So when we switch this off, you can see here some of the peaks going more or less over
[00:01:10] 0 dB slightly, and we can just prevent this by enabling here peak clip.
[00:01:16] There's also an auto gain here, which automatically compensates for everything that you do inside
[00:01:23] of the plug-in, or what the plug-in or the compressor does to your signal.
[00:01:27] So for instance, if you compress really hard, it tries to match the output gain to the input
[00:01:32] gain, and then you can use the mix knob and can compress in parallel, or just compare basically
[00:01:40] the wet signal to the dry signal, and see what's actually happening to the signal.
[00:01:46] And I really like to see this in all kinds of compressors, and probably yes, I don't know.
[00:01:54] So that's that.
[00:01:55] So for instance, if I change some of the settings, for instance here the threshold, pulling
[00:02:00] this down, you can see it's waiting for me to stop actually changing something, then
[00:02:04] it learns the new gain reduction output and then compensates so it matches the input signal.
[00:02:16] So maybe pull this more down here, like this.
[00:02:24] So I would never do this on my master, it's just for showing, just as an example, you
[00:02:30] can see the plug-in is working very hard.
[00:02:43] So because of this auto gain compensation here, you can really mix in just the dry signal
[00:02:50] a little bit, or maybe to 50% and have like parallel compression, and the output of this
[00:02:58] plug-in is not overpowering the dry signal, that's the reason behind that.
[00:03:02] You can also switch this off here, and just use manual make-up gain if you want to do
[00:03:07] that.
[00:03:10] Only downside is if you compress very, very hard, then you go up, right, it's clipping,
[00:03:16] and now it's back to normal.
[00:03:19] So when you change your, of course, attack times, it's changing.
[00:03:33] And because of this visual history meter here, wave history meter, you can see really what's
[00:03:38] going on when the plug-in starts to compress something, how much it compresses, and you
[00:03:42] can kind of dial in some of the settings visually.
[00:03:46] Also here, this characteristic needle of this bus compressor is also in there, if you really
[00:03:51] like to have this, also with this hold meter or hold needle here, also in there.
[00:03:58] So it's really more or less the same thing as the Ableton Glue Compressor.
[00:04:03] It's the same style, and yeah, if you just switched from Ableton Live, maybe to Bitwig,
[00:04:09] and you missed the Glue Compressor, now you can just use my plug-in here, which is also
[00:04:13] available as clap plug-in, a VST3, also on Mac with AU, and as a standalone.
[00:04:20] And it really works on all systems, or I try to make it work on all systems.
[00:04:24] There are always some bugs, of course, with Linux.
[00:04:27] Everyone has a different system, different distribution, different window manager, or
[00:04:34] whatever this is called.
[00:04:36] So whenever the system does a small little nuance, it's different, so it's always hard
[00:04:41] with Linux, but I try to make it work.
[00:04:44] Because the main intention for these plug-ins is for me, I want to switch at some point
[00:04:49] to Linux, and I want to have some plug-ins there that are working natively there, with
[00:04:56] no iLock, with no subscription, with no serial numbers or anything like this, no telemetry,
[00:05:04] no email I need to submit.
[00:05:06] And I also want to have my own features, or features set, and I also have a strong opinion
[00:05:12] about all kinds of settings and how everything should be, and you know, so I try to express
[00:05:19] myself with this a little bit, and make it free for everyone.
[00:05:24] And I hope most people enjoy it.
[00:05:27] Anyway, so besides that, we have also here a side chain, we can use external side chain
[00:05:35] with the plug-in, you can just select, in Bitwig here you can use a different instrument
[00:05:39] or different bus, just to use that as a signal to compress maybe a bus against a cave charm.
[00:05:47] I don't know what you want to do with that.
[00:05:50] Also your side chain high pass.
[00:05:53] So if you have a side chain, you can side chain more or less the signal path.
[00:06:03] Also if you have a big kick drum maybe in there, and it reduces the, it amplifies the
[00:06:11] gain reduction too much, you can just take the kick drum out here with the side pass,
[00:06:16] and then have a different outcome.
[00:06:19] So that's also in here.
[00:06:23] What else?
[00:06:24] Yeah, you can also manually learn if you want to do that, it's actually not needed.
[00:06:29] And there are some overlays here, some help overlays, right?
[00:06:32] You can see here and read what's going on there, also you have to learn.
[00:06:37] It's maybe not perfect yet, but it's the first version.
[00:06:42] So let me know what you think, maybe just download that, give me some feedback.
[00:06:47] I know this is here, I want to have this here on the same line, this is not correct, but
[00:06:52] you know, it's first version.
[00:06:55] I also changed here with the resizing, some people complained about this with my older
[00:07:00] plug-ins that it's actually not saving the state, right?
[00:07:04] So when you open up a new project or an older project with this plug-in on, it doesn't remember
[00:07:09] what kind of size you dialed in.
[00:07:11] And some people have bigger screens, smaller screens, and I want to have different sizes.
[00:07:17] So the state is here saved to the project, and there's a default state which is 100%,
[00:07:23] and it also remembers this I think across the plug-ins.
[00:07:29] I'm not sure if this is the current version here, kind of, yeah.
[00:07:37] Presets are not in there at the moment.
[00:07:38] You can save your own if you want to and share it.
[00:07:42] Did I explain that the quality dropped down?
[00:07:44] Yeah, you can change basically the oversampling for the real-time plug-in, which is what you
[00:07:49] see at the moment here.
[00:07:51] Or if you bounce the audio or render the audio, you can say I want to have eight times oversampling
[00:07:56] every time I render or bounce to disk.
[00:08:01] That's also in there.
[00:08:02] Two states, we can compare two different states.
[00:08:08] If you have different settings, you're not sure what kind of setting is better.
[00:08:14] You can compare these two and then also make sure you copy one to the other slot.
[00:08:19] And yeah, that's also pretty default for most plug-ins, I would say.
[00:08:24] So this is the glue plug-in and like I said, updates coming to the other plug-ins as well.
[00:08:32] I just want to put this out here and get some feedback on it.
[00:08:37] So if you have some, let me know in the comments down below, I track every comment.
[00:08:41] It goes straight directly into my feedback system or my community feedback system and
[00:08:51] just put it in the comments, okay?
[00:08:54] I catch everything.
[00:08:56] And yeah, the other plug-ins are getting some updates too next week or in the next two weeks
[00:09:01] and the state here is also coming to the other plug-ins as well.
[00:09:07] And yeah, that's basically it.
[00:09:09] Let me know what you think.
[00:09:11] Try it out.
[00:09:12] It's completely free.
[00:09:13] It's on my web page here, polarity.productions polarity minus glue.
[00:09:19] I can read some stuff here, head over to the download page for Windows, Mac or Linux.
[00:09:25] Like I said, you don't need to subscribe to anything.
[00:09:27] I don't want to email, there's no iLog or telemetry, anything.
[00:09:32] It's just free to use, okay?
[00:09:34] Nothing is in there.
[00:09:35] I don't care.
[00:09:36] I am more or less founded by my patrons, which I really, really thank because I can just
[00:09:44] take my time and develop some stuff and make sure everything is great and free and useful.
[00:09:52] That's the most important thing for me.
[00:09:55] Anyway, that's it for me for this video for this Sunday.
[00:10:00] Let me know in the comments down below what you think.
[00:10:02] Leave a like, of course, and see you next time.
[00:10:06] Bye.

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