The Kush Audio team released an emulation of an interesting hardware compressor with deep musical history. In particular, the unit saw notable use at the Abbey Road Studios on later Beatles and early Pink Floyd records.
Its progenitor is the old Altec 436B compressor, an all-valve vari-mu American design originally envisioned for telephone, broadcast, and other public address applications. Abbey Road staff modified them with an output attenuator and six-position recovery switch to control the compressor’s release time. Said switch also pioneered the Hold feature which prevents a compressed signal from returning to its original level. The modified compressor was christened EMI RS124, although staff simply referred to them as “the Altecs.”
Back to the future
Back to modern days. The AR-1 plug-in models the hardware original but also extends it functionally. Values are visible for all controls and the Release knob is fully variable instead of stepped. However, there are Releases 1-4 which you can click to emulate the original timings. Additionally, the compressor’s Attack and Release times can be much faster than on the hardware, as expected from modern compression. No longer needed, the Infinite Hold feature from the original has been relinquished.
Moreover, Kush rethought the Tone knob to balance between typical digital and analog sonic characters – that is, an emphasis on either bite or “beef”. Additionally, a 60Hz sidechain switch has been added in order to mitigate unwanted pumping effects, as well as an IO Gain link to eliminate dramatic volume swings resulting from driving the compressor’s input. As a final tweak, the Threshold knob can completely disable compression while keeping input and output circuitry intact. This way, the AR-1 can be used for its tube distortion.
Price and availability
The Kush AR-1 compressor can be purchased standalone for USD 99 or as part of the OG Kush Complete subscription bundle. It costs USD 10 a month / USD 100 a year and lets you use all current and upcoming Kush plug-ins for the subscription period. Additionally, a 10-day trial version of the compressor is available.