Universal Audio Capitol Mastering Compressor plugin is a digital emulation of the legendary CM5511 tube compressor, a rare piece of hardware used extensively at Capitol Studios. This plugin recreates the rich, smooth sound of the original hardware unit, of which only four were ever built. Designed to capture the essence of vintage Fairchild 670 and Gates Sta-Level tube limiters, the Capitol Mastering Compressor offers a unique blend of classic warmth and modern flexibility. It features a user interface that closely mimics the original hardware, complete with VU meters and stepped controls for precise, repeatable settings. The plugin goes beyond the capabilities of the original hardware by including additional features like a saturation control, mix knob, and mid/side processing options. Universal Audio has meticulously modeled two of the original CM5511 units to ensure authentic sound and behavior across various audio sources and genres.
Pros:
• Authentic emulation of a rare and highly sought-after hardware compressor
• Versatile enough for both subtle mastering tasks and more aggressive compression on individual tracks
• Additional modern features like mid/side processing and saturation control enhance its utility
Cons:
• Steep learning curve due to unique control layout and behavior
• Limited attack and release options may not suit all users or material
Capitol Mastering Compressor boasts an array of features that blend vintage charm with modern functionality. At its core, the plugin offers the classic compression characteristics of the original CM5511, known for its smooth, musical response and ability to add cohesion and polish to mixes. The user interface closely resembles the hardware, with mirrored controls for left and right channels (or mid and side when in M/S mode).
The input control allows users to drive the compressor’s circuitry, affecting both the amount of compression and tonal coloration. The plugin offers a sidechain filter with three options: flat, 365 Hz, and 700 Hz, each with a 6 dB/octave slope. This feature helps tailor the compressor’s response to different frequency ranges, particularly useful for controlling low-end content.
Threshold, attack, and release controls are presented in a stepped fashion, mirroring the original hardware’s design. The attack and release each offer five positions, ranging from slow to fast. While this might seem limiting compared to fully variable controls, it encourages users to work within the sweet spots of the original unit. The ratio control, an addition not present on the hardware, provides five options from 2:1 to 10:1, expanding the plugin’s versatility.
One unique aspect of the Capitol Mastering Compressor is its output control, which only attenuates the signal. Users must use a separate gain control to compensate for gain reduction, a design choice that may take some getting used to but can lead to more intentional gain staging decisions.
Universal Audio has enhanced the plugin with several modern features. The saturation control allows users to add harmonic content, ranging from subtle warmth to more aggressive coloration. A mix knob facilitates parallel compression techniques, while the headroom control allows for fine-tuning of the plugin’s internal operating level. The mono fold feature helps tighten low-end content, particularly useful in mastering scenarios.
The plugin can operate in stereo, dual mono, or mid/side configurations, offering flexibility for various mixing and mastering tasks. Additionally, it includes modern metering options, including dBFS and LUFS readouts, bridging the gap between vintage aesthetics and contemporary loudness standards.
In comparison to similar plugins, the Capitol Mastering Compressor stands out for its specific emulation of a rare piece of hardware. While many compressor plugins aim for a general “vintage” sound, this one captures the nuances of a particular unit used on countless hit records. Its closest competitors might include other high-end mastering compressor emulations like the Softube Weiss MM-1 or the Brainworx Townhouse Bus Compressor. Capitol Mastering Compressor offers a unique blend of vintage character and modern features that sets it apart. Its stepped controls and specific sonic signature may be less immediately versatile than some alternatives, but it excels in imparting a particular flavor of compression that’s hard to achieve with more generic tools. The addition of mid/side processing and saturation controls gives it an edge in modern mastering scenarios, allowing for more precise stereo image manipulation and tonal shaping than many of its vintage-inspired counterparts.
This plugin is best for:
• Mastering engineers seeking to add cohesion and polish to final mixes
• Mix engineers looking to add vintage warmth and character to individual tracks or busses
• Producers working in genres that benefit from subtle, musical compression
• Audio professionals familiar with vintage hardware who want that specific “Capitol sound”
Universal Audio Capitol Mastering Compressor plugin offers a compelling package for those seeking the sound of a legendary piece of hardware. Its faithful recreation of the CM5511’s smooth, musical compression characteristics, combined with thoughtful modern additions, makes it a versatile tool for both mixing and mastering applications. The plugin’s unique control layout and behavior require some investment to master but can yield rewarding results for those willing to learn its intricacies. While it may not be the most flexible or intuitive compressor on the market, its specific sonic character and the pedigree of the original hardware make it a valuable addition to any digital audio workstation. The Capitol Mastering Compressor shines in situations where subtle glue and vintage warmth are desired, but it’s capable of more aggressive settings as well. Its ability to operate in mid/side mode and the inclusion of a saturation control extend its usefulness beyond mere dynamics processing, allowing for creative sound shaping at the mastering stage. Despite its relatively high price point, the plugin represents a unique opportunity to access the sound of an extremely rare and coveted piece of analog gear, making it an attractive option for professionals and enthusiasts alike who are chasing that elusive “hit record” sound.