In real life, the Fairchild Limiter weighs about 67l bs, looks like something from a 1950s space program and costs up to $50k.
Originally created for the final mastering stage before the actual cutting lathe (back when a record was cut from acetate) it was designed to stop transients from throwing the cutting head about, which would in turn create unpredictable vinyl pressings. With Lat and Vert control - eg the depth and LR movement of the head under control it had a ludicrous number of valves and transformers (20 valves and 14 transformers) at the input and output stage as well as super fast response (we're talking microseconds).
In more modern times, the sound of the Fairchild even without any limiting going on would be reached for to add that certain something or "glow" to pretty much any recording in studios that can afford one, they go for up to $30k with a daily hire rate of $150.
Universal Audio have already created a Fairchild emulation for their UAD-1 powered plugins platform, but with the advance in DSP power - they are now at UAD-2 with more powerful Sharc processors, they've been able to model more accurately the characteristics of the many valves and transformers of the input and output stages. Fortunately for them, they have access to a legendary 'golden" unit at Ocean Way Studios.
This new version comes with various enhancements to the original controls - a blend control for parallel processing, adjustable headroom, sidechain filters, as well as two models, the stereo or mid/side 670 and the mono and generally more aggressive 660.
We enlisted the help of ace recording and mix engineer Tosh of WIJ productions, who uses the Apollo Quad as part of his recording and mixing rig to take a look.
One thing that was apparent, there is a more silky and subtle nature to the sound when compared to the original Fairchild UAD-1 version. What also is clear is that it's one of those processors that although subtle, is sorely missed when switched out. All those usual descriptors such as glue and sheen do apply- it can add a special magic sheen to pretty much any recording. And with the use of the Mid/Side mode, where you can process the centre signal (eg bass drum/vocal) separate from the sides, it is possible to create a more stereo signal - this is something that SPL have been doing with some of their recent hardware mastering processors.
The 670 appears to take around 4% of processing on a Quad UAD system so you should be able to use several instances.
For a detailed description of the new plugins, please see the above video.
The UA Fairchild Limiter Collection is available now as part of the 7.4 software update with the bundle available from the UAD store at $299