Overview

In 2015 SPL released the IRON mastering compressor based on an original concept.

Their goal was to conceive a compressor that provided a pleasant, melodic-sounding, transparent compression, inspired by the vintage compressors of the radio era. But they wanted it to be versatile enough to adapt perfectly to the needs of modern mastering studios.

Thus, the IRON combines not only the sonic virtues of legendary vintage tube compressors with the advantages of the High Dynamic 120 V operating voltage in a single unit. It also sets a new benchmark in terms of tube compressor technology, with the innovative implementation of a parallel dual-tube circuit.

Iron is a variable-bias tube compressor, often called a “Vari-Mu” design. Unlike most standard variable-bias designs, which use the bias of a single tube for compression, Iron uses a dual circuit topology. This means, the incoming signal is split between two tubes via a specially designed Mu-Metal iron transformer, running in parallel and then recombined. One tube is a 12AX7/ECC83 and the other a 12AU7/ECC82. Each tube yields a slightly different compression curve and feel.

The Attack and Release parameters have six different settings ranging from Slow to Fast. The times are not constant, they vary according to the Rectifier circuit selected: There are six different Rectifier settings available with different diodes (Germanium, Silicon, LED, mixed).

Mastering is not the only domain where the IRON sets new standards. It can also be used to process subgroups or individual signals, like vocals, bass, guitar, strings, etc.

Features

  • Variable Bias Tube Compressor
  • Parallel Dual Tube Circuit
  • Custom Mu-Metal Iron Transformers
  • Feed-forward resistive Vactrol-Opto-Isolator
  • Six different Rectifier settings available
  • Sidechain that allows you to choose between Off, four sidechain-filter presets or an external sidechain signal
  • In Link mode, the Threshold, Tube Bias, Attack, Release, and Rectifier parameters, as well as the Sidechain EQs, are controlled with the right side (channel 2) of the unit
  • Master out features an additional, Passive Equalizer with two fixed sounds
  • Brainworx plugin only features such as TMT, M/S Processing, Mono-Maker and Stereo Width, Parallel Mix and Headroom

Audio Examples

Industry Reviews

  • Gentry Studer

    Gentry Studer

    I downloaded the plug in, I've had to shoot it out against the real thing on every project, just to see how it stacks up. You guys did an amazing job with the plug in. Everything from the color it… Read More

  • Michael Romanowski

    Michael Romanowski

    I use the hardware SPL Iron for my mastering everyday. What I love about it is the tonal and dynamic flexibility is has for every style of music. And it’s always smooth and musical. Brainworx… Read More

  • Brendan Duffey

    Brendan Duffey

    When I need a tool that gives me a plethora of gain, tone and shape controls the Iron Mastering Compressor is the first thing I turn to. The Iron Plugin has all the controls features of the… Read More

Customer Reviews

  • SPL Iron

    ★★★★★
    by Hans
    Absolut fantastic. You can put this thing on every signal and then feel how the tears run down your cheeks. I beg you to try out the demo and I promise you'll buy the IRON long before the demo period… Read More
  • SPL Iron Kicks Ass

    ★★★★★
    by Audiomilitia
    Awesome Emulation , Sounds fantastic ...Been A/Bing with the Uad shadow hills and i must say i think i prefer the Iron , seems to dial in a bit more bite , Digging it in M/S . Stereo width ,Tube and… Read More
  • Nice Tone

    ★★★★★
    by CLNyc
    This is quickly becoming my fave compressor. As usual I applaud PA for putting out a DSP version. I put it on a mix and got a pleasing light compression right away. I just sounds nice.
    I almost… Read More
  • Wouu

    ★★★★★
    by K r a d . F a c e
    one the best compressor vst ,I have tried on a long time for drums , bass buss and master.
    Only you have to tried.
  • Spl Iron

    ★★★★★
    by Jordan Schultz
    I own most of Plugin Alliance and i never wrote a review, but this plugin is just BRILLIANT!!!!
    Its puncy, warm, clean, agressive, fat, its what ever you want it to be ... just must have… Read More

Specification

Supported Plugin Formats
AAX DSP, AAX Native, AU, AAX AudioSuite, VST2, VST3

Supported Operating Systems
Mac OS X 10.9 through 10.13
Windows 7 through 10
Pro Tools 10.3.10 or higher or most VST/VST3/AU-compatible hosts running on a supported operating system

Mac
Intel CPU only (minimum 2 GHz recommended)

PC
Intel-compatible CPU with SSE2 instruction set (Pentium 4 compatible or higher; minimum 2 GHz recommended)

System Requirements
Display resolution: 1440 × 900px or 1280 × 960px or higher
Memory: 2 GB RAM

Downloads

With the Installation Manager, you can select, download and install just the Plugin Alliance products and formats you need for your system.