Minimal Audio Flex Chorus

Chorus is one of the oldest BBD (bucket brigade delay) effects, arriving hot on the heels of the first analogue delay pedals. Essentially, chorus is a modulated short delay that adds pitch wavering, and when this signal is added to the dry sound, the result approximates the sound of two instruments or voices playing the same part but with small timing and tuning variations. Alternative designs were created that ran two slightly different modulated delays at the same time, in order to disguise the cyclic nature of the effect, and so the multi‑voice chorus was born. With analogue delay chips each new voice adds to the expense, but software emulations can add stereo operation and multiple voices more easily!

Minimal Audio’s Flex Chorus, which supports the usual Mac/Windows plug‑in formats including AAX, can have up to 24 voices, and offers overall control over the delay time and modulation depth. A single set of modulation controls has adjustable rate and adjustable randomisation, with a sync‑to‑tempo option as well as a display that shows the left and right delay taps wandering back and forth along a timeline. In the centre are controls for Width, Time and Feedback, with the EQ controls placed to the right and being switchable between Multi‑band and Filter types. (Multi‑band is designed to preserve the low end and high end of the source sound.) Sliders at the bottom of the window set the input level, wet/dry balance and output level, and a soft‑clip limiter can be switched in to catch any accidental overloads.

The number of voices can be set to 2, 4, 8, 12, 16 or 24, and while there are no controls for individual voices, it can be seen from the display that the modulation amount, delay times and direction of movement varies between voices for different modulation and delay settings. The modulation is disabled when Depth is set to zero, so that the delay controls can be automated to create custom effects.

Additionally, Minimal Audio have added two operational modes: Smooth and Glass. Smooth is said to work according to human frequency perception, so as to produce a deep, rich sound, whereas Glass mode takes a multi‑stage approach for brighter, crystalline effects. There are numerous presets supplied to demonstrate the possibilities, and there’s also a random button for help choosing presets when you’re in need of inspiration.

The CPU load of this plug‑in is fairly modest even with all 24 voices switched on.

Adding more voices uses more CPU, but the CPU load of this plug‑in is fairly modest even with all 24 voices switched on. Also, to my ears, using two or four voices gives the best balance between movement and complexity, though using a lot of voices can add density and texture where you want that effect. Having adjustable delay time and feedback allows for effects that veer towards comb‑filtering at the shortest delay times, with more noticeable doubling at the other extreme. There’s an impressive range of stereo chorus effects available, from all the old guitar standbys and honky‑tonk pianos to heavy detuning, faux reverb and shimmering soundscapes that go way beyond standard chorus effects.