Comparing Different Opto Compressors

Understanding the differences in Opto compressor designs and how and when to use them.

Beat Construction

Purchase to view this tutorial

By purchasing this tutorial, you'll get immediate access - your purchase helps create new and exciting content and this site survive!

£1.00Add to basket

When it comes to compressors we producers are spoilt for choice. We not only have access to every type of compressor topology (design/type) available in the form of software plugins but we now have many variations of the same topology offered by different manufacturers. Deciding which manufacturer to use becomes a subjective decision as all well specified plugin manufacturers conform to the standards and builds provided by the software equivalent hardware manufacturers. However, not all like for like topologies behave in the same way and this tutorial will demonstrate the differences that exist between manufacturer builds of the same topology.

The type of compressor that is used both at the mixbus and at the channel stage and is most popular for vocal processing is the opto compressor. To understand the subtle differences between different manufacturer builds we need to first understand how opto compressors work.


Opto (optical) – Uses a  photocell as a detector and a light bulb to determine the gain reduction. Different light sensor types and illumination sources affect the gain reduction in different ways. The time lag between the photo cell and detector makes for a slow attack and release and this makes this type of compressor perfect for processing vocals, performing gentle automatic gain changes and mastering. The most famous hardware opto compressors are the LA-2A and Avalaon AD2044.

In this video I run a drum beat sequence through two distinct opto compressors. I explain how opto compression works and show you how to use each compressor making sure to explain each and every parameter. I end by demonstrating how the two opto compressors differ in result even when the same settings are used for both compressors.

Plugins used in this video:

FabFilter Pro C

Softube Tube-Tech CL1B

Topics covered in this video are:

  • Understanding the differences in Opto Compressor Designs
  • How and when to use them
  • Various Opto Topologies and behaviour
  • Understanding Gains
  • Ceiling and Headroom
  • Coloured and Transparent Compression
  • Working with Ranges
  • Tips and Tricks