The renowned Manley Stereo Variable Mu compressor/limiter is a favorite of producers and recording engineers. Anyone who has heard theFairchild 670 in action has an idea of the Variable Mu's capabilities.
Its adjustable attack and release settings are optimized for mixing and mastering, but are flexible for most tracking situations.
How it works is that the unique 5670 dual trioide is at the center of the peak-reducing and compression action - and it's constantly being re-biased by the vacuum tube rectified side-chain control voltages. The Varible Mu's Compress mode is soft-knee 1.5:1 ratio while the sharper knee Limit mode starts at 4:1 and moves to a more dramatic ratio of 20:1 when limiting over 12dB. Interestingly, the knee actually softens as more limiting is used. Distortion can be creatively used by turning up the Input and turning down the Outputs while using very little or no compression.
