Review: Empirical Labs Arousor

A plug-in that rekindles your passion for compression
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When I reviewed the Empirical Labs Distressor for Mix magazine in 1996, I was blown away by its superb sound, operational ease, and outstanding versatility. I achieved such impressive results on vocals, guitar, saxophone, flute, clarinet, cello, percussion, drums, and bass that I wrote, “Once in a while a product comes along with ‘classic’ written all over it. And in a sense, this product is actually a classic already.” That proved to be true, with more than 30,000 units sold.

Though the Arousor is ostensibly a plug-in version of the Distressor, the two are not identical either in features or functionality. For example, although the Arousor sports virtual representations of the same large Input, Attack, Release, and Output controls found on the Distressor, those controls don’t behave in precisely the same way, and directly editable parameter values are displayed on the virtual knobs.

Empirical Labs' Arousor includes soft clipping and variable saturation, among other features that differentiate it from the company's popular Distressor.

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Other differences include major revisions to existing features and the way they are implemented. The Distressor’s Detector function, for instance, affects compressor response by modifying the control signal using fixed highpass and band-emphasis filters, and a single button cycles through eight settings that not only select the filters but also combine them with the Stereo Link function in various ways.

Instead, the Arousor’s Detector section provides a widely variable highpass filter for preserving the uncompressed sound of lower frequencies such as bass and kick drum, and a fully parametric sidechain equalizer that allows you to zero in on the frequencies you want to emphasize or de-emphasize.

The Distressor’s Audio button cycles through combinations of a highpass filter (this time in the audio path) and two flavors of fixed distortion, but the Arousor offers a Soft Clipping section with a variable Saturation control that gradually increases the amount of mostly odd-order, tape-like distortion. Also, the Arousor features an Attack Modification control that shapes the attack characteristics differently from the Attack control, and a Blend control for parallel compression. Two more compression ratios (1.5:1 and 8:1) were added, as were 22 factory presets.

One Distressor feature missing from the Arousor is Opto mode, which emulates the performance of vintage optical compressors, though it will be added in a future update—which brings us to an important consideration regarding cost.

At $349, the Arousor isn’t cheap. However, in addition to receiving the current version, purchasers will be entitled to free updates until 2020, and many will be significant, according to designer Dave Derr. “Backward and forward compatibility are critical,” he says. “Sixteen additional functions have already been provided for, including Opto mode, which I’m very excited about, as virtual opto is capable of far more than any physical optical circuit.”

I tested the AAX version of the plug-in in Pro Tools 11. Like its hardware forebear, the Arousor worked wonders with both male and female vocals and a wide range of instruments, as well as on the stereo mix bus. I also got excellent results using it on modern electronic sounds from ambient atmospheres to synthetic percussion, as well as on sampled orchestral mixes.

The Arousor is a unique compressor that imbues any sound with increased vibrancy and presence. Download the 14-day trial and see if it doesn’t arouse your compression passions.


Superb sound. Intuitive interface. Super-flexible. Price includes two iLok activations.


Comparatively pricey.


Barry Cleveland is a San Francisco-based journalist, guitarist, composer, recording artist, and audio engineer. Learn more at