It starts with the Distressor's familiar large white knobs and LED gain reduction meter and ratio selection indicators running the width of the GUI. Those familiar with the 1U Distressor hardware unit will recognize that Arousor has a similar looking front panel only folded in thirds to fit into the DAW screen.

But that is just the start of differences--enough differences that Empirical Labs' Dave Derr decided it was really a new product and purposely, did not call it a Distressor plug-in.

Arousor has the large Input, Attack, Release, and Output controls like the Distressor and I liked that all the controls knobs display their currently running parameter values. You can directly type in and enter values by double clicking or just mouse over and easily move the controls conventionally. Arousor has ten ratio choices including 1.5:1 and 2:1 (these two not on the Distressor) and Rivet (aka "NUKE" from the Distressor) a brickwall limiter ratio.

The Distressor has been a reliable tool to re-sculpt harmonic coloration and carefully add saturation precisely. Arousor's Soft Clipping section does this well using a broadband Saturation control for soft clipping peaky sources. This is as organic as any saturation/coloration I've ever heard from a plug-in--it is not exactly like real hardware but rather has its own unique sound.

Similar to tube saturation or analog tape recorder compression and combined with a particular Attack knob setting and using compressor ratios toward limiting (8:1 or higher), I found on clean electric guitars the Saturation knob set above mid-way produced more noticeable odd-harmonic distortion as indicated by the plug-in's %THD meter. At lower signal levels, the distortion is said to be more even-harmonic for a generally more subtle, warmer tone.
(Check out the presets!)

The Arousor's Attack time control ranges from 50-microseconds to 40ms at the slowest and there is a clever attack time shape modifier that works in conjunction with the Attack time setting. The Attack Modification control changes the "shape" of the attack's rise time curve whereas the Attack time control changes the overall attack time.

Somewhat like the way an envelope generator works, increasing the AtMod control will reshape the initial rise time portion of the attack to lengthen or shorten it in a non-linear way. Depending on the Input level, Ratio and the Attack time control knob setting, it is easy to recreate the attack characteristics of any number of classic, vintage compressors and limiters--the very reason many mixing engineers own and use so many different vintage units.

The bottom third of the GUI has a variable 6dB/octave (1st order) high pass filter set up in the sidechain. It is adjustable from: 12Hz (off) to 1kHz. Next to it is a single frequency parametric Detector Sidechain EQ with a 40Hz to 10kHz range, +/-30dB boost/cut, and variable bandwidth from a super sharp Q from a tenth of an octave to a broad Q of five octaves. There is no bypass switch--so the Boost/Cut control should start straight up at unity 0dB.

This feature works amazingly to "chop out" a band of audio by extremely compressing a narrow range of frequencies. Arousor will work as a single frequency de-esser or low frequency de-popper. Loads of sound design ideas come to mind here for exploration for my next guitar effect treatment.

Finally, there is Wet/Dry Blend control---but I only run this at full "10" for 100% of the Awesome Arousor! Highly recommended!

The stereo version is linkable and there are 18 valuable presets named for what they work well on such as Small Drum Room or Rock Lead Vocal Evener.