One of the most powerful mixing tools available to the 21st century producer, the automatic or ‘intelligent’ EQ is a radical variant on dynamic EQ that constantly pulls the full (or deliberately constrained) frequency spectrum of the incoming signal towards an internally established optimal target in real time by applying hundreds of dynamically responsive peak filters to it. It’s all you need to smooth out irksome resonances and general harshness, and here we’re taking in five of the leading options.
oeksound Soothe 2
One of the first plugins to put this whole intelligent EQ concept on the audio engineering map in the first place, the original Soothe was an instant hit, despite suffering from a few shortcomings. Released three years later, the sequel not only filed all the rough edges off its predecessor – most notably dropping the bottom of its frequency coverage down from 250Hz to 20Hz, and greatly expanding the filter modes and types – but also added the very effective ‘Soft’ processing mode, Attack and Release parameters, mid-side processing, sidechaining and more.
Soothe 2’s workflow and UI are a collective delight: the interactive ‘inverted’ EQ-style depth curve makes it easy to shape the amount of processing applied across the spectrum, the Sharpness knob sets the ‘resolution’ of the process by narrowing/widening the notches, and the rest of the controls enable plenty of adaptability without overcomplicating matters. It all adds up to a truly remarkable resonance-taming plugin that requires so little user input to dramatically improve almost any signal that you won’t be able to resist trying it on every element of the mix.
Sonible smart:EQ 3
Sonible’s brainy equaliser has been honed over three versions to become the amazing beast it is today, offering instant and highly effective sorting out of resonance issues and general harshness within a beautiful and intuitive interface. Step one is to select a target profile (Drums, Bass, Piano, Acoustic Guitar, Vocal High, Vocal Low, Universal, etc), then quickly capture a few seconds of input signal so that the machine learning algorithm can come up with – in its opinion – the optimal response curve for your source material. You can then pull the ‘weighting’ of the curve up and down to intensify, relax and even invert it, and totally customise it by clicking regular multimode filter nodes in and dragging them around. Up to six instances can be connected within a project, too, working together to resolve masking problems between tracks or busses; the mid/side implementation is exemplary; and user profiles (modifying the factory profiles using the standard filters) can be saved out, so you can even develop your own signature smart:EQ ‘sound’ of sorts. Brilliant stuff.
McDSP SA-3
Hot off the grill, McDSP’s fully automatic EQ builds on the algorithms of their acclaimed SA-2 Dialog Processor to serve up a far more general-purpose system for smoothing out sound sources of all kinds. While SA-2 is a five-band equaliser with centre frequencies set to achieve its very narrow remit (polishing dialogue tracks), SA-3 ups that number to over 1000, covering the full frequency range, in order to make it applicable to the gamut of musical instruments and sung vocals. The specific issues targeted here are described as “spikes and persistent overtones”, and the Focus control steers the algorithm towards your desired balance of processing between them. You can also manually tweak the response curve in the spectrum display, dial up/down suppression of harmonics above the fundamental frequencies being processed, and route in a sidechain key for steering the suppression using an external signal.
As anyone who’s ever spent any time with SA-2 would expect, SA-3 is astonishingly good at what it does, nuking errant resonances and overtones in all track types just as effectively as its spoken word counterpart. Check out Paul Maunder’s first look right here.
Soundtheory Gullfoss
Taking a different tack to other intelligent EQ plugins, Gullfoss bases its automatic frequency correcting process on a model of the human auditory system that “decides how to prepare the audio so that your brain can get the most information out of it”. What that means in more literal terms is a sort of light-touch clarifying and decluttering effect that does indeed make busses and mixes – those being its stated objectives – sound qualitatively ‘better’ in a way that other plugins don’t necessarily. This unique implementation brings with it a similarly quirky workflow, however, and getting accustomed to Gullfoss’ controls and response requires a bit of practise and experimentation.
The two main parameters, Tame and Recover, suppress and counteract masking between elements within the signal respectively, slanted one way or the other by the Bias control; while Brighten and Boost can be brought into play for dynamic high- and low/mid-frequency emphasis/deemphasis if required. Happily, metering is plentiful, so you can see at a glance how much taming, recovery and brightening is taking place; and the affected frequency range is easily adjustable, should you only want to fix up a particular part of the spectrum.
As long as you understand what it’s doing and handle those controls with care, the improvement that Gullfoss makes to any (generally well balanced) mix really can be transformative, with a natural cleanliness that never fails to amaze.
Baby Audio Smooth Operator
By far our cheapest entrant, Baby Audio’s “intelligent signal balancer” deploys FFT-based spectral compression to actively conform the input signal to match a user-defined response curve, making it viable for more wilfully creative treatments as well as the primary corrective role that’s probably its main selling point. Application couldn’t be more straightforward: drag the centre node in the main display up and down to set the main spectral compression threshold, then offset that across the frequency range with the other four EQ nodes, and use the Focus slider to adjust the width of the filters. A sidechain input enables cross-channel ducking, and the combination spectrum/gain reduction analyser is highly informative. It’s a simple setup that keeps you moving fast but allows for a lot of flexibility, it sounds great, and the price is a definite plus.
Have you relinquished control of your equalisation to the terrifying whims of the machine? Sing the praises of your intelligent EQ of choice in the comments.