Dynamic equalizers have been around for a while. Historically, they were outboard units, making them expensive and limited to one stereo track at a time. When plug-ins of this type appeared, most were confusing to my eyes and sounded artificial or hyped to my ears. Fortunately, that's not the case with the recently released Sonnox Oxford Dynamic EQ.

Oxford Dynamic EQ's GUI is the most elegant Sonnox representation ever, with controls that allow novice users to start getting sounds without opening the manual. The frequency display may look like that of a standard EQ, complete with real-time response curves. But clicking on one of the bands gives you access to more than just the standard frequency, Q, bell/shelf mode, solo, and mute controls. You'll also find Dynamics, Threshold, and Target Gain. What this means is that the band can boost or cut toward the Target Gain, based upon Dynamics ratio and Threshold level. Hence, a chosen band of a kick drum could be boosted only on big hits, or a band on a hi-hat could be reduced when it's too loud. Each band also has an Offset Gain (the static level of the band before dynamics are triggered), which works in conjunction with Target Gain to adjust the amount of dynamic gain change available to the specific band. Digging deeper, you'll also find controls for Attack, Release, and sidechain selection/EQ, among many other advanced parameters.

Oxford Dynamic EQ has a very natural sound. It can correct an issue without distracting the listener with pumping or artifacts. Although numerous factors go into sound quality, one of the main reasons it sounds so smooth is due to its Q implementation. The manual explains that the plug-in leverages the Type 3 algorithm from the legendary Oxford R3 EQ [Tape Op #26, #32]. Type 3 is proportional?Q, which means that low amounts of cut or boost use a relatively broad filter, but as the boost or cut is increased, the Q becomes narrower — a more natural-sounding effect to the human ear.

To the casual observer, a dynamic EQ looks like a multiband compressor. And it would be reasonable to question if there is even a need for a dynamic EQ, given that a multi-band dynamics processor can do similar things. But they're not exactly interchangeable, and even when they both could be used to tackle the same problem, the results can be very different. I like to explain that a dynamic EQ is a little mixing engineer who sits inside the workstation and rides the gains of an equalizer, as little or as often as needed.

De-essing during the mastering stage is tough. The best attack is usually a manual process — either spectral editing or individually adjusting the gain on each offending syllable. But this is very time consuming. With Oxford Dynamic EQ, I am able to come closer to the results I can achieve through manual editing. Another use is to seat the plug-in on harsh moments of guitar or cymbals during dense sections. On the single "Vesper Bells" by Delicious Pastries, I was able to tuck in two problem frequencies in the upper midrange that were poking out during two sections of the song. Cutting those frequencies with a full-time EQ was taking away too much energy, and using a sidechained compressor just made them more dense.

Most of my examples have dealt with cutting or limiting certain frequencies. But the ability to boost a mix element can also be a lifesaver. Suppose the artist wants the snare to crack a little louder on the chorus. When the Trigger mode is set to "Above," dynamic gain change takes place when the signal goes beyond the Threshold level. That means no boost is added until the band's level reaches the threshold. This avoids putting a full-time boost across the track. Just find the snare fundamental, set the trigger to Above, and add that 0.5 dB that makes it poke out at key times. It's almost like cheating.

My comments above are from my use of Oxford Dynamic EQ in a mastering context. Let me now hand over the review to recording and mix engineer Don Gunn, who discusses how he employed the plug-in for mixing.

–Garrett Haines

I love EQ, and I love compression; mangling sounds into something they weren't before, is fun and can add excitement to music. These tools can also be used subtly to gently fix problems. (Fixing is not as much fun as mangling — but we gotta do what's right for the job, right?) As much as I love something like a Neve 1073 or API 550b for colorful, broad-stroke EQ, they generally aren't the tools I reach for when problems arise. Enter Oxford Dynamic EQ. I've used almost all of Sonnox's other plug-ins for years (Oxford EQ has been my go-to utility equalizer for years), so I had high expectations for the company's first all-new product in quite some time.

While I track a number of the projects I produce and/or mix, I also get sent many sessions to mix only, so the tracking end of things is out of my control; this sometimes reveals problems with the source tracks, due either to incorrect recording techniques, or to poor/questionable monitoring where these issues remained hidden. These are exactly the situations in which Oxford Dynamic EQ shines.

When a source sounds "dark" or "wooly," rather than automatically reaching for the boost on the upper-mids (let's face it, I'm a booster, and it's more fun to turn things up than down), applying Oxford Dynamic EQ to dynamically cut the particular frequency range that's causing the mud can suddenly make the track feel appropriately brighter, without having to boost anything. Applying "normal" EQ after the Oxford feels like I'm starting from a more level playing field, as the problem areas have already been addressed, and now I can focus on shaping the instrument into the mix.

Each band's dynamic detection can be either internal or external; internal is based on the signal of the source track, while external is a sidechain from another track or bus. Want to push down the fundamental of a bass each time the kick drum hits? Easy!

Oxford Dynamic EQ is the perfect tool for screechy strings or too-brash horns, and being able to solo bands is immeasurably helpful to zero in on problem frequencies and set appropriate amounts of reduction. Un-solo the band and listen to your now-smooth string or horn part. Similarly, many bass guitars have dead spots on the fretboard, or conversely, notes that jump out. Find those notes and use Oxford Dynamic EQ to either cut the boomy ones or boost the weak ones when they occur, without affecting the overall tone of the instrument like a static EQ would.

Vocals are especially well-handled by Oxford Dynamic EQ. Too much proximity effect? Use the low-shelf to help push down those boomy chest-notes, without neutering the lows all of the time. Sibilance an issue? Solo the highest peaking band and find the worst of the harshness, give it a tight Q, and cut until those pesky esses are gone. Can you tell I love this thing, and I'm finding plenty of uses for it?

On a stereo track, the individual bands can be set to act on the stereo signal, the left or right separately, or even the Mid or Side for M/S processing. This is brilliant for synth pads that are clouding up the center, but you want to boost the airy sides. Set a low-mid band in Mid mode to dynamically cut the muddiness, and use the high shelf on the Side channel to open it all up.

–Don Gunn

We truly live in a time with an embarrassment of riches; there are plenty of choices for all of our processing needs. Sonnox Oxford Dynamic EQ isn't the least expensive, nor is it the most full-featured dynamic EQ available. But after using it on real projects, we both believe you get what you pay for. Sonnox has always released top-quality titles, but the combination of workflow and sound quality offered by Oxford Dynamic EQ may make this the company's best plug-in to date.

Tape Op is a bi-monthly magazine devoted to the art of record making.

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