The Mel Scale defines the range and position of auditory frequency bands that make up human hearing. It is generally accepted that there are 26 of these bands between 0Hz and 20kHz, with each band relating to a critical frequency that elicits a reaction from the basilar membrane in the inner ear. The ear can only perceive a frequency when it's a certain distance from those adjacent to it, with those distances dependent on the frequency itself. What this means is that in comparison to a regular graphic EQ, whose frequency bands are distributed according to musical intervals, the position of EQuivocate's bands are defined by what human hearing perceives as equal. The result is a subtle, somewhat psychoacoustic difference that translates into an EQ that endeavours not to sound like an EQ at all.
EQuivocate's interface is simple and clean. You're given the choice of three different skins, though the default option (labelled "Modern") is the least garish and makes the most sense in terms of usability. The majority of the plug-in window is taken up by the graphic EQ, inside of which are the 26 bands. Each band can be individually dragged up or down by +/-12dB. With the Draw Curve option enabled, it's possible to do the whole lot in one go. For a product that prides itself on accurate, natural sound, being able to draw in frequency curves by hand does come across as a bit of a gimmick, but it's hard to deny it's a fun one that increases the potential for the odd happy accident. Soloing bands is achieved by clicking the dedicated solo buttons along the top of the EQ graph, while toggle-able input and output meters for each band provide useful visual feedback about what's happening on a per-band level, as well as the spectrum as a whole. However, the speed at which they react can sometimes make it hard to get a handle on the average shape of the curve. Having something like the option to see the RMS of each band might be a nice addition here.
Below the gain meters are values showing the peak frequency of each band. Since the bands in EQuivocate are not always symmetrical, it's worth noting that the peak is not necessarily the centre-point of the band. It's possible to shift the frequency of each band by dragging these up or down the spectrum, thereby diverging from the distribution set out according to the Mel Scale. This is visualised by a triangle that adapts dynamically to how you move it's peak across the spectrum. Drag across an adjacent band and it is effectively pushed out of existence. It's a unique, and admittedly slightly baffling, approach to get your head round, especially considering graphic EQ bands are traditionally static along their x-axis. But after a bit of playing around, it all begins to make sense.
Input and output meters, showing Peak, RMS and Peak Hold values, reside on the left and right sides of the plug-in, with gain controls for each. The output level control's Auto function compensates for any changes in overall level bought about by the EQ, functioning in the same way as makeup gain on a compressor. This makes the EQ's overall effect on the audio much easier to ascertain when mixing and protects your ears and monitors from any wild spikes in volume.
The most interesting part of EQuivocate's feature set is Match EQ. It isn't unique—FabFilter's Pro-Q2 has a similar option, while Logic has it's own dedicated plug-in—but the Mel Scale offers impressively smooth and useful functionality. Updating the EQ curve in real time to match the incoming audio from its sidechain input is an enjoyable sight as the gain faders shimmy up and down. Hitting the Match EQ button again stops the fun and freezes the current state of the curve. How much you need to match the EQ from one audio source to another depends on the kind of work you do or the music you make. Recorded vocal takes on different days and need to get them in line with one another? This is going to come in handy. For day-to-day electronic music production, it's perhaps less useful. However, EQuivocate is able to invert the resulting EQ curve. This effectively removes any conflicting frequencies, which is very handy for slotting sounds into a busy mix. It's by no means a cut and dry solution to any mixing woes you may be having, but it's certainly a useful tool to have in the box.
So how does it sound? Stick to the Mel Scale and any frequency adjustments, no matter how subtle or drastic, perfectly fit into the overall picture. Remove bands and drag things around and you start to produce some weirder results (Richard Devine's presets are, as you'd expect, a pretty good example of this). Comb filtering and odd, lo-fi timbres are particularly good examples of how far the plug-in can be pushed out of its comfort zone.
On the face of it, EQuivocate doesn't come across as the most exciting of plug-ins. After all, it's just another EQ, right? But it's fresh, human-centric approach to graphic equalisation combined with the powerful, dynamic-sounding Match EQ feature means it's actually far more useful than appearances might suggest. Add to that the fact that it's free until the end of October and you've no excuse not to give it a listen.
Ease of use: 4.1