- Michael Krusch
Part 10 of our review of the different compression modes in the Schwerkraftmaschine
When experienced audio engineers listen to many of the hits from past decades, they're probably thinking: "Damn, those VCA compressors had it all going on."
What distinguishes a VCA chip
The VCA chip represented a breakthrough in electrical engineering. Every other limiting technology had disadvantages to be worked around.
The VCA changed all that: It delivers linear compression, can handle normal audio levels, reacts exponentially to control voltage and can work across an extremely broad range ( >120dB), with low harmonic distortion, quick reactions and extremely low noise.
The characteristic VCA sound proved a fine match for the rise of electronic sounds from analog synths and drum machines. Already a fixed component in high-quality mixing boards, its trademark sound spread to all musical styles and remains a gold standard.
Featured in our Crème bus compressor and mastering equalizer, the VCA continues to cut a fine figure, leading Wes Maebe (2016 Pro Sound Engineer of the Year) to call it "...one of the best compressors I've heard in a long time…" .
The VCA grabs powerfully, without adding in a lot of character of its own. When presented with rhythmic transients, it delivers snappy attacks and defined compression to shape the typically punchy rock/pop sound.
The compression can crunch hard. It can also blend into the background and stay transparent. This transparent sound makes the overall compression nearly invisible.
VCA and Vari-mu - How they work together
How can a Vari-Mu compressor, which inherently works with its own distinct control character, compress linearly like a VCA compressor?
First, you have to strip the tubes of their own character. The Schwerkraftmaschine analyzes its own tubes, identifies their characteristic curve and factors that tube character into the processing the control signal.
Once calculated properly, the Schwerkraftmaschine then compresses linearly like a VCA.
It's a neat trick, and allows the device to replicate the behavior of other compressors without its own tube character shining through.
Unlike its archetype, the attack, release and ratio here are all infinitely variable, with no need to stick to pre-defined levels. The tendency of a Vari-mu to pull back the bass tones somewhat can be counteracted using side chain filters if needed.
This blend of the base tube sound and that peculiar VCA character is, as far as we know, unique to the Schwerkraftmaschine, and opens up fascinating new worlds of sound.