Empirical Labs Prof Punch-Knuckles

Table of Contents

Introduction

The phrase "a modern classic" is definitely over-used. If something survives longer than a single season, it's too often called a modern classic. In reality, a true modern classic is rare, maybe a "once in a decade" thing, and very few pieces of audio equipment will ever become a real modern classic. But there is definitely one unit on that list, and that's the Distressor from Empirical Labs. Dave Derr's clever compressor design combined with the unique and colorful saturation circuits quickly made the Distressor a must-have for all recording studios.

Since its inception and release in 1995, Dave Derr's Distressor circuit has found its way into more Empirical Labs products, such as the versatile Preamp/Compressor unit Mike-E, which saw the addition of a dry/wet control (yay!) as well as a dedicated saturation meter (from "Warm" to "Toasty"!)

Prof. Punch-Knuckles is the uncontrollable, but highly intelligent, love-child of those two. With precise metering and great versatility, it shows an analytical and professor-like side, while it's not afraid of throwing punches and make a great fuzz. It has a warm, professorial, side, but isn't afraid to totally crush your audio to pieces. It is smooth, warm and musical. A friendly punch in the gut.

Behind the scenes, Prof. Punch-Knuckles has three different modes: Toasty, Crunchy and Distress. All of these three can be used either as a subtle flavor-inducing spice to your tracks, or as a very audible distortion. But the Professor excels at subtle distortion, and that's where you will hear the biggest difference between Toasty, which is the saturation circuit of Mike-E, and Crunchy, the preamp distortion of Mike-E. But Distress is the king. That's the Distressor compressor on its most aggressive setting: setup for distortion.

User Interface

At the top of the user interface you'll find the combined THD/gain reduction meter.

  • GR scale (top): In Distress mode, it uses the dB-scale on top (gain reduction).

  • THD scale (bottom): In Toasty and Crunchy modes, it uses the THD (%) scale at the bottom.

The top scale (GR, from 0.05 dB to 20 dB) is used in the Distress mode, while the bottom scale (THD, from 0.5% to 100% is used in Toasty and Crunchy modes.

Drive
Sets the amount of distortion/compression. It's a gain compensated drive control, meaning that you probably don't have to compensate the output level using the Output knob.
Distortion
Sets the distortion type of Prof. Punch-Knuckles:

  • Toasty: Based on the saturation in the compressor of Mike-E, it's a warm and colorful distortion that is best suited for THD levels below 10-14%

  • Crunchy : Based on the preamp distortion of the Mike-E. A slightly harder, and more crunchy, distortion than Toasty. Great for shaving off transients from a drum track.

  • Distress: The compressor circuit of Distressor and Mike-E, set to its fastest and most brutal setting. Used conservatively, with about 3-5 dB of gain reduction, it can make the snare or vocals to sit in the mix. Or you can crank it up to really squash the drums and use the Mix knob bring back the transients from the unprocessed audio.

The distortion mode selector is the heart of Prof. Punch-Knuckles, with three distinct types of distortion. Toasty and Crunchy are modeled from the distortion circuits, the Distress mode is a combination of compression and distortion.

Out
Sets the output level after the effect
If you open the Extended Features panel to the right you will find additional precision metering (True Peak, LUFS, RMS, etc), a gain match feature, precision gain controls and a "Smooth Bypass" function.

Low Cut, High Cut and Tone are processed after the distortion. Mode is affecting how the distortion sounds, and the Mix blends the distorted signal with the dry signal (before the Out control).

Low Cut
12 dB/oct, slightly resonant, high pass filter placed after the saturation.
Tone
A +/- 12 dB tilt filter, placed after the saturation.
High Cut
12 dB/oct, slightly resonant, low pass filter placed after the saturation.
Mode
Choose between three different tonal qualities of the saturation

  • XFRM: The "transformer" tone will emphasize the distortion of the low end.

  • Wide: A wide-range distortion

  • Tape: Emphasizes the distortion in the top end.

The difference between the modes (XFRM, Wide and Tape) is easier to hear with a moderate amount of distortion. The more you slam it, the more similar the different modes will become.

Mix
Sets the blend between the dry (unaffected) audio and the wet (processed) audio. The Mix control is situated before the Out level, so that the blend between dry and wet is unaffected by the output level.
In/Out Meters
Input meter and output meter showing the max value of L/R channels.
For precision metering, use the meters in Extended Features.

Credits

Anton Eriksson - modeling, signal processing
Cameron Clark -- signal processing
Dave Derr, Empirical Labs -- original hardware design, testing, presets
Willie Kunstadter, Empirical Labs -- testing, presets
Jeff Goodman, Empirical Labs -- testing, presets
Niklas Odelholm, Maxus Widarsson - product design
Ulf Ekelöf - UI 3D rendering
Patrik Holmström, Fredrik Jansson - framework programming
Johan Bremin - quality assurance