Released in 2012, SoundRadix' SurferEQ combined equalisation and pitch tracking, shifting its five main frequency bands and two filters (high- and low-pass) up and down to stay focused on a sound, rather like a synth's filter keytracking.
In our original review we concluded that, although it was very handy for correcting timbral unpleasantries of various kinds in vocals and solo instrumentation, its very specific functions and inability to deal with polyphonic material made it a niche proposition.
What we thought SurferEQ needed above all else was audio sidechain and MIDI inputs, so that the EQ bands could be shuttled around independently of the signal being processed. There was already an automatable Override Pitch control onboard, after all...
Happily, it seems the development team was listening, as both MIDI input and sidechaining have since been added to the plugin - the first with version 1.2, and the second with the full v2, which we're looking at here. SurferEQ2 (VST/AU/ AAX/RTAS) also works in a number of other helpful new features, as well as introducing a completely redesigned non-skeumorphic, Retina/HiDPI-compatible GUI.
It looks great and includes a keyboard graphic in the main display, showing the centre/corner frequencies of all seven colour-coded bands in musical pitch.
MIDI triggering works in three modes: incoming MIDI overrides the internal pitch detection; internal pitch detection is disabled and Surfing bands are toggled on and off and follow incoming pitch via MIDI note on/off; and internal pitch detection is disabled and MIDI notes override internal pitch detection and act like an audio gate.
The sidechain, meanwhile, does exactly what you'd expect, swapping the pitch detection over from the main input signal to an external one. As well as making SurferEQ2 a more viable option for polyphonic material, the sidechain and MIDI inputs enable frequency- specific ducking of one signal, opening up a new range of potential usage scenarios.
Available to the centre band only, SurferEQ's Harmonic Filter cuts or boosts the harmonics of the target frequency, although, as noted in our original review, it's better suited to creative sound design than corrective work.
In v2, its original four modes (each defining the resonance, shape and relative depth of each filter) have been doubled to eight. There's also a zero-latency mode, adjustment of the Surf time between notes (1-5000ms), and you can now limit the ranges of the high/low filters in Surf mode.
SurferEQ2's new features certainly up its game, particularly the sidechained frequency ducking, MIDI triggering and Spectral Gate; and its ability to dynamically sculpt the frequency make-up of instrumental sounds and vocals without compromising their harmonic balance is truly remarkable.
The other really big new feature added in SurferEQ2, alongside the external MIDI and sidechain pitch tracking, is the Spectral Gate. Each band has a GTE button, and with it turned on, that band is activated when the input or sidechain signal crosses the threshold set by the GTE THR slider on the left, and deactivated when it drops below it - or vice-versa in Reverse mode. The speeds at which the bands rise from zero to full gain and fall back to zero are determined by the Attack and Recovery Time controls.
The Spectral Gate works particularly well in conjunction with the sidechain - ideal for returning the gains of ducked frequencies when the ducking source is silent, for example - but is just a great inclusion, generally, bringing a dynamics-related angle to the plugin that's useful for basing the response of the EQ on the loudness of the signal.
For the average electronic producer, however, it's still a very 'specialist' plugin. We're also slightly disappointed to find that the parametric Q still snaps to four fixed settings, the narrowest of which isn't nearly tight enough for surgical work.
That said, ultimately, SurferEQ2 is a unique, undeniably powerful sonic tool that not only elevates v1's already accurate, natural sounding 'EQ surfing' of monophonic material to impressive new heights, but also steps the whole concept up in terms of flexibility.