Empirical Labs EL-DS DerrEsser De-Esser Module


If you are mixing your vocals with outboard gear then a De-Esser is critical to have near the front of your vocal chain. Get rid of those pesky esses before your compressors later in the chain make then even louder and more annoying. Empirical Labs has been one of the most used and respected companies making dynamics in the modern era and this DerrEsser is in league with their other high end studio standards.


The DerrEsser, designed as an API 500 series module, is a versatile dynamic filtering device, primarily known for its effective de-essing capabilities. Here’s a breakdown of its features and functionalities:

Key Features:

  1. De-Esser Mode (“DS” Mode):
    • Function: In its basic mode, the DerrEsser functions as a de-esser, a tool that attenuates high-frequency sibilance in vocals or other audio sources.
    • Mechanism: It uses a crossover technique to split the audio signal into high and low-frequency ranges. The high frequencies are then processed by a Voltage Controlled Amplifier (VCA) which dynamically reduces their level, smoothing out harsh or spiky sounds in a musical way.
  2. Dynamic Filtering:
    • Beyond De-Essing: Unlike traditional de-essers, the DerrEsser offers broader dynamic filtering capabilities, making it a multi-functional tool.
    • Crossover Technique: The device’s use of crossover filters allows it to manage different frequency ranges effectively, providing flexibility in shaping the tonal characteristics of the audio.
  3. Voltage Controlled Amplifier (VCA):
    • Control and Precision: The VCA in the DerrEsser provides precise control over the gain of the high frequencies, enabling smooth and musical attenuation without affecting the overall balance of the audio.


  • Vocal Processing: Ideal for controlling sibilance in vocal tracks, making them smoother and more pleasant without losing clarity.
  • Instrument Balancing: Useful for taming harshness in instruments like cymbals, guitars, or other sources with prominent high frequencies.
  • General Audio Processing: Can be used in various audio processing scenarios where dynamic frequency control is required, enhancing the flexibility and usability of the device in a professional audio environment.

The DerrEsser’s ability to function as both a de-esser and a dynamic filter makes it a valuable tool for audio engineers looking for a versatile solution in a compact API 500 series format. Its musical approach to handling high frequencies ensures that it can be used effectively in a range of audio applications.


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