WAVES CLA-2A Compressor User Guide

: June 9, 2024
: WAVES

Table of Contents

WAVES CLA-2A Compressor
Product Overview
About the Modeling
Product Usage
Introduction
- Product Overview
Quick Start Guide
Interface and Controls
- CLA-2A Controls
Appendix: CLA-2A Controls
References
Read User Manual Online (PDF format)
Download This Manual (PDF format)

WAVES CLA-2A Compressor

Product Overview

The Waves CLA-2A is a plugin that models the characteristics of the original hardware compressor units used by Chris Lord-Alge to create punchy and highly- compressed sounds. The plugin includes many of Chris’s personal presets and delivers the distinctive sound of his favorite classic compressors.

About Chris Lord-Alge
Chris Lord-Alge is a highly-regarded audio engineer who has worked with many popular musicians including Green Day, U2, and Pink. His hard-hitting mixes have transformed the radio soundscape and introduced a new sonic vocabulary.

About the Modeling

The unique sonic behavior of analog gear has been painstakingly modeled and incorporated into the Waves CLA-2A plugin. The hardware was modeled at reference levels of 18 dBFS = +4 dBu, meaning that a signal of -18 dBFS from the DAW to the hardware unit will display a meter reading of 0 VU (+4 dBu).

The most important analog behavior is Total Harmonic Distortion or THD, which is defined as the ratio of the sum of the powers of all harmonic components to the power of the fundamental frequency. THD is usually caused by amplification and changes signal shape and content by adding odd and even harmonics of the fundamental
frequencies, which can change the overall tonal balance.

In the original modeled hardware, a T4 optical device determines compression behavior. When strong signals are introduced to the compressor input, release time constants lasting several seconds may result. In certain cases, this may cause the same passage to sound different during successive playbacks, as the Release does
not return to the unity position.

Product Usage

Install the Waves CLA-2A plugin on your DAW.
Open the plugin and choose one of Chris Lord-Alge’s personal
presets or create your own custom settings.
Adjust the input and output gain according to your needs.
Use the compression knob to apply varying degrees of
compression to your audio signal.
Monitor the output meter to ensure that your signal is not
clipping or distorting.

Introduction

Product Overview

About the CLA-2A
The CLA-2A is modeled on a hand-wired, tube-based compressor originally produced by Teletronix in the early 1960s. Initially intended for use in broadcast, the original used an electro-luminescent optical attenuator called “T4” for gain reduction. Unlike many other designs, electro-luminescent circuitry doesn’t add distortion when it modulates the sound. (Tubes, however, do, and we made sure to model that distortion.) Additionally, the inspiration for the CLA-2A’s frequency-dependent attack and response speed made it an instant favorite of audio engineers. However, many consider its most unique feature to be its program dependent, multi-stage release, which was achieved using a 2-stage photo-electric cell. With a Frequency Response of 30Hz to 15kHz (+/- 1dB) and < 0.5% THD, the original provided up to 40dB of gain limiting.

Widely known among audio pros and listeners alike for his punchy sound and extreme compression techniques, Chris gave us exclusive access to model his most prized processors, and worked closely with Waves through every phase of development. Together with many of his personal presets, these precision models deliver the distinctive sound of CLA’s favorite classic compressors.

About the Modeling
Many different elements contribute to the unique sonic behavior of analog gear. Waves painstakingly modeled and incorporated the characteristics of the hardware into the CLA-2A, in order to fully capture and replicate the sound and performance of the original equipment. The hardware was modeled at reference levels of -18 dBFS = +4 dBu, meaning that a signal of -18 dBFS from the DAW to the hardware unit will display a meter reading of 0 VU (+4 dBu).
These are some of the most important elements of analog behavior:

Total Harmonic Distortion
Perhaps the most important analog behavior is Total Harmonic Distortion or THD, which is defined as the ratio of the sum of the powers of all harmonic components to the power of the fundamental frequency. THD is usually caused by amplification, and changes signal shape and content by adding odd and even harmonics of the fundamental frequencies, which can change the overall tonal balance. THD can also change peak output gain, usually by no more than +/- 0.2-0.3 dB.

Variable Release Times
In the original modeled hardware, a T4 optical device determines compression behavior. When strong signals are introduced to the compressor input, release time constants lasting several seconds may result. In certain cases, this may cause the same passage to sound different during successive playbacks, as the Release does not return to the unity position. This behavior is identical to that of the original hardware, and should not be a cause for concern.

Hum
Waves modeled both 50Hz power current and 60Hz power current. If you listen closely, you will hear that there is a difference in hum level between 50Hz and 60Hz. Since hum is unique to each region and dependent upon local electrical conditions, you may find that the modeled hum is different than the hum already present in your studio, and may not be suitable for your particular use.

T4
In the original hardware units, the T4 optical device is responsible for the amount of overall compression and compression characteristics. These components are quite vulnerable to wear and tear, and need to be replaced, ideally, every 2 to 3 years. Depleted T4 devices result in up to 80% less compression as compared to newer components. In the course of our research, we discovered that up to 90% of T4 components in use today have never been replaced. This means that the majority of users are working with devices that compress far below the original manufacturer specifications.
If you are used to the performance and behavior of an original unit, and find that the modeled plug- in provides more aggressive compression than you are used to, it may be that you have grown accustomed to a worn-out T4 component.

Components
WaveShell technology enables us to split Waves processors into smaller plug- ins, which we call components. Having a choice of components for a particular processor gives you the flexibility to choose the configuration best suited to your material.
The CLA-2A has two component processors:
CLA-2A Stereo — Two-channel compressor, with one detector for both channel paths
CLA-2A Mono — One-channel compressor

Quick Start Guide

The CLA-2A offers 2 main controls for compression, as well as additional controls for fine-tuning.

Using the Compress/Limiter toggle, select Compressor (approximately 3:1 ratio) or Limiter (approximately 100:1 ratio).
Use the Peak Reduction control to set the amount of compression desired.
Use the Gain control to adjust make up level after the compression.
Use the VU Meter to monitor Input, Output, and Gain Reduction levels.

Interface and Controls

CLA-2A Interface

WAVES CLA-2A Compressor-FIG2

CLA-2A Controls

Gain controls the makeup gain.
- Range: 0 to 100 (in 0.01 steps)
- Initial Value: 40.00
- Reset Value: 32.28 (unity gain)
Peak Reduction controls the amount of signal compression.
Please note: The scale is not linear and has been adjusted to conform to the exact scaling of the modeled unit. Thus, there may be more compression than expected at certain steps, as with analog gear (most common Peak Reduction range of the LA-2A is between 30 to 50).
- Range: 0 to100 (in 0.01 steps)
- Initial Value: 46.00
- Reset Value: 0
Compressor Mode selects compression or limiting.
- Range: Comp, Limiter
- Default: Comp
HiFreq increases voltage amplifier gain in the peak reduction circuit, for frequencies above 1 kHz, leaving lower frequencies unaffected. When set to Flat, the CLA-2A will provide equal reduction to all frequencies. The more you move away from the Flat position, the less sensitive the compressor is to lower frequencies, resulting in less compression. This control may also be used as sort of a deesser.
- Range: 0 to 100 (in 0.1 steps)
- Initial Value: 50.00
- Reset Value: 100 (flat)
Analog controls analog characteristics caused by noise floor and hum, based on the power supplies of the original units.
- Range
  Off, 50Hz, 60Hz
- Initial Value: 60Hz
- Reset Value: Off
Mix controls the balance between the compressed and the uncompressed signal.
- Range: 0% to 100% (0.1% increments)
- Default: 100%
Trim sets the output level of the plugin.
- Range: -18 to +18 dB (in 0.1 dB steps)
- Initial Value: 0
- Reset Value: 0
VU Display toggles between Input, Gain Reduction, and Output metering.
- Range
  In, GR, Out
- Default
  GR

The WaveSystem Toolbar
Use the bar at the top of the plugin to save and load presets, compare settings, undo and redo steps, and resize the plugin. To learn more, click the icon at the upper-right corner of the window and open the WaveSystem Guide.