Audio, Reviews

NUGEN Audio SEQ-S, a unique linear phase equaliser

NUGEN Audio’s SEQ-S is a linear phase equaliser. It supports mono, stereo, 5.1, and 7.1 surround and provides sonic sculpting and EQ matching including stereo mid-side operation, automated spectrum analysis, curve smoothing, and a unique direct-draw spline interface for corrective applications.

SEQ-S features a phase profile that is linear across the frequency spectrum, which should result in natural-sounding EQ changes and produce minimal phase artefacts. SEQ-S also includes a unique resolution setting that can be used with high precision in the low frequencies.

I installed SEQ-S on a Mac with Logic Pro X, Reason 7 and Sound Forge Pro installed. As expected, the plug-in worked with Logic Pro and Sound Forge Pro but not with Reason 7. In addition to the SEQ-S plug-in itself, a Send plug-in got installed as well. The Send plug-in is used with EQ matching. The Send plug-in allows for sonic fingerprinting to match one recording to another. Although you would want to use this feature to capture the atmosphere of similar source audio and transfer it to the current project, I also tested matching a voice recording with a recording of a didgeridoo. The resulting audio was much like what you can achieve with Sony SpectraLayers 2, but much faster and much more user-friendly.


The plug-in itself is unique in the controls it offers and the way those controls work. First of all, it can be zone-less, meaning you can tune the spline curve across the whole frequency range. The EQ curve can be — must be — drawn in the window from its initial flat appearance to anything else. This would result in an awkwardly scribbled result if not for its automatic visual smoothing and two controls: envelope smoothing and banding. The banding option determines the frequency position of control points in the EQ curve. There are six to choose from: Thirds, Sixths, Chromatic, Bark, Mel and Bark Thirds.

These are not just handy, but each has its own use. For example, the Bark banding arranges bands according to the Bark scale, which is a psycho-acoustic scale. Drawing the curve with the Bark scale results in a different curve ‘design’ than the other banding options.

Zones can be added by clicking the Zones button and dragging the Zones handles so they encompass the frequency range you want to limit your edits to. The zone control can be inverted by locking the points inside instead of outside. Equally simple is creating multiple envelopes. There are three buttons of which the top selects the envelope, while the bottom part turns it on or off.

SEQ-S has three envelopes available. Each can be assigned a single or combination of channels. The Assign button pops open a HUD in which you assign the envelopes. I tested with stereo material and could assign to Left, Right, Mid and Side.


The Advanced button reveals some seven new features. The active EQ envelope can be inverted with a button click, but if you create a zone first, only the zone will be inverted. The banding option lives here too. In addition, you can set the FFT size from 1024 to 16384 — the size will affect the EQ resolution. The user guide advises on how you need to set the size for optimum performance/quality. There’s also a Dither button that converts output from the built-in 64-bit floating point accuracy to lower bit-depths. Available dithering algorithms are rectangular, triangular and Gaussian.

Finally, Match EQ is very easy to do as well. You add the Send plug-in to the track which you want to match your EQ to, and record from the source to a snapshot or a template. A number of options are then available, including recording time and channel selection.

Sound quality

I compared the SEQ-S equaliser with Apple’s Linear EQ and iZotope Ozone’s equaliser sound quality as well as user-friendliness. In terms of sound quality, Ozone is an absolute top-notch product. It comes with many great-sounding presets that minimise the time needed to get a good result. Nevertheless, I found that I could get a better sounding audio clip with SEQ-S — which was something I did not expect as the other two equalisers are certainly no toy. The adjustments I made resulted in more detail using SEQ-S than with the other two.

NUGEN Audio Send

Part of the reason for the better result is that with Ozone’s and Apple’s equalisers you’re limited by the lower resolution and the parametric controls, which disallow to shape the curve exactly the way you want the mix to sound. With SEQ-S I sort of expected that drawing the curve would result in broad and therefore rough adjustments, but I got exactly the opposite. I could choose to have dramatic edits, but by default changes were subtle with no harshness introduced whatsoever.

In addition, SEQ-S’s EQ invert button should provide a subtle technique for creating space in a mix. In a typical music project, by “sampling” the vocal and then using the EQ invert button to apply the inverted curve to the backing, users can gently create specific space without unnecessarily damaging the original tonality of the underlying audio.

Last but not least, when I tested SEQ-S with low frequency material — a piece played on a cathedral organ in which only the very low registers were used — it did not add rumble to the sound the way the other two equalisers did.

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J.D. – Copywriter – Tech. Writer – Editor at Visuals Producer – Contributor at Photoshop User, Studio Daily – Sub-editor at RedShark News