The core concept behind Multipass is wonderfully straightforward.
A VST/AU effects plugin, it splits the input signal into up to five discrete bands, each with its own effects lane, into which you can drop as many effects modules - called "Snapins" - as you like (CPU permitting, of course).
As well as the five band lanes, Snapins can also be inserted into the full-frequency signal before or after the band splitter, in the Pre FX and Post FX sections on the left and right. To marry it all up, there's also a comprehensive modulation system and mixer controls, with which all sorts of dynamic effects patterns can be created.
Each Snapin is actually a full plugin that can also be loaded into a VST/AU host on its own, and you buy Multipass with five, ten or 17 Snapins included (not of your own choosing, alas). The 'Basic' Multipass bundle ($99) consists of Chorus, Delay, Gain, Limiter and Stereo Snapins - useful, but not much to get inventive with apart from Stereo, with which you can get some cool L/R modulations happening.
The Producer Pack ($159) adds in Compressor, Distortion, Filter, Haas and Phaser. The Filter is the highlight here, with a choice of seven curves, and Cutoff, Q and Gain parameters that can be assigned to any of Multipass' modulation sources for dynamic and rhythmic tonal movement.
Applying Distortions (there are five types onboard) to individual bands and blending them in subtly can bring some interesting character to the table, but they tend to be overly crunchy by nature.
The full Modular Madness bundle ($249) adds in Bitcrush, Comb Filter, Formant Filter, Frequency Shifter, Pitch Shifter, Resonator and Trance Gate. Of these, the Formant Filter and Trance Gate offer the most creative potential, the former accentuating vowel sounds for morphing between using an X/Y pad, the latter a step-sequenced slicer.
All of the above Snapins can be bought after the event for $19 each if you don't initially shoot for the Modular Madness bundle. Interestingly, Kilohearts' other two effects plugins - Faturator (another distortion) and Disperser - can also be loaded into Multipass as Snapins. They cost $39 each.
To activate a band, you simply turn it on; to set its frequency range, you drag the handles around in the Spectrum/Band Splitter area above. Clicking empty space in a band lane brings up a menu of your installed Snapins from which to make a selection, and Snapins can be freely dragged around and copied from one lane to another.
Each band has its own Solo and Mute buttons, and every Snapin can be individually bypassed. It's all beautifully intuitive.
At the bottom of each band are Gain, Pan and wet/dry Mix knobs, plus a Post knob, which governs the amount of processed signal sent to the subsequent Post FX lane. The Pre FX and Post FX lanes behave in exactly the same way as the Multiband lanes, with the same set of mixer controls minus Post.
The modulation system is very deep. Each modulation source (eight Macros, two LFOs, two envelopes and eight MIDI controllers) is effortlessly assignable to multiple parameters from throughout Multipass and its loaded Snapins, and the envelopes and LFOs can be triggered by any of the five bands, MIDI note-on messages, or an external sidechain signal.
A good number of presets are included with Multipass, but it's so easy to use that you'll be coming up with your own mad effect chains in no time. The range of effects and the interaction between them is impressive, and the whole thing positively invites tweaking and experimentation.
As noted, the filters are the highlights - modulating the Formant Filter provides hours of entertainment and endless exciting rhythmic patterns while the lowlights are the distortion and saturation algorithms, which are a bit crunchy and unpleasant. Some tape-and valve-style warmth wouldn't go amiss.
Multipass is one of the slickest modular systems of any kind that we've come across in software. Being able to add effect elements into the signal path wherever you like is awesome, and the modulation setup turns it into a hugely inventive and dynamic processing environment.
The range of Snapins available is good and no doubt will only get better both in numbers and types . We'd love to be able to load in full third-party plugins, though, and it would be awesome if the platform was opened up to other developers; but as it stands, Multipass is a fantastic multieffects plugin with a very bright future.