With some neat features to control how the compressor and expander interact, there’s more to this module than meets the eye.
It’s always nice to try a product from a company you haven’t crossed paths with before, and it’s especially nice when it’s something that offers rather more than you first imagined. The product that brought this thought to mind is Frap Audio’s Dynamics 2806, a mono compressor and expander that comes in the form of a ‘double‑wide’ 500‑series module. Frap, who may be new to the world of studio processors but have been active in the Eurorack modular synth scene for a while, describe their 2806 as belonging to the same family of ‘advanced dynamics processors’ as the ADR Compex. That famous device was released in the late 1960s (see our SOS February 2014 article for more about it) and, legend says, was used for the iconic drum sound on Led Zeppelin’s ‘When The Levee Breaks’. Although I was pretty sure the 2806 wouldn’t help me play like John Bonham, I was intrigued and keen to hear what it had to offer.
There’s a lot going on in this compact design and there are many controls, so I was impressed that the interface didn’t feel overly busy or cluttered. At its heart are two dynamics processors, each with its own control signal but sharing the same THAT 2181 VCA chip for signal processing. The inputs are electronically balanced, while the output runs through a Lundahl transformer.
One processor is a feedback compressor and the other a feed‑forward downward expander; the top half of the front panel hosts the compressor controls and the lower half those for the expander, with a few ‘global’ controls in the middle. The two processors can be used individually (either can be bypassed) or in tandem to sculpt your signal, and the LED bar meter on the left displays both the amount of gain reduction (down from the top) and the amount of expansion (up from the bottom). Clever and efficient though that is, it can make the meter pretty busy at times, and I did sometimes find it a little distracting. Both are surprisingly feature‑rich processors, and there are some clever ways to control their behaviour individually and the way in which they interact. There are extensive side‑chain capabilities too, both for refining the processors’ responses and for more creative triggering.
As you’d expect of a VCA compressor this one can be very fast and aggressive. This could be thought of as being its ‘default behaviour’, but the designers have included an impressive selection of controls that make it very malleable. For example, alongside the usual complement of controls (threshold, separate attack and release times, ratio and make‑up gain), there’s provision for parallel compression: Frap have opted for a Parallel knob that adds in dry signal without changing the level of the processed sound. The make‑up gain control can also attenuate the compressed signal, so there’s the option of starting with the dry and blending in as much processed sound as you need.
More novel features include the option to relax the compressor’s behaviour by switching to what Frap call Classic mode: the time constants become much slower and it’s easier to make the compressor ‘pump’ — think more ‘vintage’. The Priority control, just above this, is another thoughtful touch. This prevents the expander operating at the same time as the compressor (ie. the compressor always takes priority), so that it doesn’t counteract any gain reduction being applied. Yet more flexibility comes courtesy of...