MNTRA Borealis

It may look like yet another reverb plug‑in, but Borealis ploughs its own furrow by including extensive modulation facilities — there are three modulation sources plus an envelope follower that tracks the incoming audio. It also includes a master section, with a parametric EQ and dual‑mode limiter that offers modern or vintage characters. All the mainstream plug‑in formats are supported across Windows and macOS platforms, including AAX.

The somewhat unconventional‑looking interface, which looks like a sphere hovering over a bunch of rods, employs three‑axis macro controls for parameter manipulation, allowing for the creation of unusual dynamic effects. Based around 14 reverb algorithms, Borealis employs both convolution and algorithmic methodology, from classic spaces and springs to granular, shimmer, distorted, endless and freeze with some also including echo‑like effects. X, Y and Z parameters are reflected in the GUI animations.

Factory presets are arranged by character for easy searching and, once loaded, you can change the algorithms using the selector at the top left of the main Perform View screen. Clicking the logo in the top‑right corner gets you back to the Perform View from any other screen. The three control axes are represented by a circular dot, a triangle and an equals sign, and these may be dragged around the GUI to effect changes via the performance macros. A control panel can be opened on the left of the GUI showing the wet/dry mix and other parameters relevant to the current algorithm. A further narrow window can be opened that shows the control mapping, which can be Modulator, Axis Position or Manual. Curves can be adjusted or reshaped by adding and dragging points, and each modulator thumbnail can be expanded to full size, where a set of preset curves is available along with a randomiser.

A ‘+’ icon tab at the bottom of the GUI opens additional rotary controls for adjusting the basic reverb parameters, while the next tab along opens the modulation page, with settings for LFO shape, rate, intensity and so on. Shapes include custom options and sequencer‑like steps. Modulators can even modulate other modulators! The Paths section is where the modulation sources are assigned to destinations, and it’s a similar story for the envelope follower. Finally, the rightmost tab opens the master EQ and limiter.

From realistic spaces to huge ambient washes, there’s something for everyone.

By way of performance, all this would amount to nothing if the reverbs themselves didn’t sound good — but they do! From realistic spaces to huge ambient washes, there’s something for everyone, with the modulation capabilities producing reverbs that pulse and shimmer in a way that reacts to the input. I suspect that creators of ambient, lo‑fi or chillout music are the most likely to embrace the extremes but there are plenty of treatments that would work in mainstream pop too. There’s a free version of Borealis limited to a single algorithm to help you get a feel for how Borealis works, and the full version is not overly expensive. It’s refreshing to see a company like MNTRA adding useful new twists to reverb, one of the oldest effects in the recordist’s arsenal.