Polyverse Music Filterverse

There’s creative potential lurking in every filter plug‑in, but in Filterverse the possibilities are almost boundless!

A filter is far from the only element to define a synth’s sound‑design potential, but I’m sure most experienced synthologists will have expressed the ‘nice synth, shame about the filter’ sentiment on occasion! And since filters have creative uses for all sorts of sound sources, it’s just as much of a shame when you discover that the powerful filter inside your favourite synth isn’t available to process your guitar, drum or bass tracks. All of which means there’s a lot to be said for having a good, dedicated filter in your plug‑in effects folder.

As Supermodal (reviewed in SOS May 2023) ably demonstrated, Polyverse already knew a fair bit about designing creative filter plug‑ins, but recently they launched a new multi‑filter plug‑in called Filterverse, which supports all the major plug‑in formats for Windows and macOS.

Three From Many

As shown in the opening screenshot, the Filterverse GUI is divided into four main areas. The strip at the base provides access to the included presets, global Dry/Wet and Main Output controls (these can be locked to ensure that levels don’t jump out of hand when you switch presets), and a simple but effective clipper that can be set to on, off or soft clip.

Filterverse offers a number of different routing options for its three filter slots.

The top strip provides slots for up to three filter choices, and a routing tab offers five different routing schemes for audio to pass through these three slots. For each slot, there’s an impressive choice of 26 filter types, and you’re free to use these in any combination, including multiples of a particular type. I won’t waste column inches discussing all the filter options available here, but this is a good place to note that Polyverse have done an impressive job with their PDF manual for Filterverse. It provides a full reference for each filter type, along with some interesting and educational background (for example, noting that a specific filter topology exists in a well‑known hardware synth).

The filter collection includes a number of classic filter designs, of course, and the majority of these exhibit non‑linear behaviour, saturating when ‘pushed’. Equally, many of them are state‑variable, with controls to blend between states (for example, between low‑pass, band‑pass and high‑pass types), through direct manipulation of the controls, automation, or via built‑in modulation options. These classic filter types are given names such as Swiss Army Knife, Bread & Butter, Evil, or Clear Glass — a useful hint as to their characteristics for those in the know, but if that’s not you don’t worry, as the manual has all the details.

With classic filters, multi‑peak filters and even ‘non‑filter’ filters, there are plenty of tools to get creative with.

There’s a further category of multi‑peak filters capable of more complex processing. Names such as Dueling Bands (two band‑pass filters, polarity inverted), Ripples (multiple narrow filters) and Robo Comb (nested comb filters) suggest what’s on offer, but there are some pretty cool options within this group, including some experimental ones. Particularly interesting to me were Vowel, which models how mouth shape and tongue position influences vowel sounds; and Strings, which uses waveguide modelling to simulate three interacting strings. Both of these did some very interesting things on a variety of sound sources during the review period... although I must confess that I’m not entirely sure I understood how they were doing it!

The final filter group contains the ‘non‑filters’. These essentially transition Filterverse into multi‑effects territory as they include options such as Space (a creative reverb filter), Decimate (providing sample rate and sample & hold options), Cabinator (a surprisingly effective guitar amp/cab effect) and delay‑based options such as Tempolay, Tempong, TemPitch and yaleD opmeT (a type of reverse delay).

The upper half of the GUI shows the controls for the currently selected filter slot. Aside from providing access to the control set for the specific filter within that slot, the Cutoff control includes a neat graphical representation of the filter behaviour and serves as a visual guide while you familiarise yourself with the characteristics of each filter type. The Filter In/Out, Dry/Wet, Pan, Cutoff and Resonance controls are present in all the filters. The additional sliders vary in number (up to a maximum of four) depending upon the filter type selected. It’s also true that, for some of the less ‘filtery’ of the filter types, the controls may actually represent parameters that are not conventionally found on a filter. Usefully, the labels adjust themselves to help you find your way around.

Modulation Sensation

In the lower half of the GUI, Filterverse boasts some equally impressive modulation features. Here, you get up to eight slots to fill with any combination of the available modulation sources, of which there are also eight options: ADSR envelope, envelope/step sequencer, oscillator, envelope follower (yay!), random value generator, pitch detector (ooooh!), MIDI/CV input and Meta Knob. The Meta Knob makes a great target for assigning to a rotary hardware controller using MIDI Learn, for hands‑on control. Note also that if your DAW supports the required routing then Filterverse can receive both MIDI note/controller data and (via a side‑chain input) CV data.

Eight modulation source slots provide plenty of ways to inject some movement into your sounds.

Pretty much every parameter within the three filter sections can be designated as a target for modulation, targets can be subjected to multiple modulation sources, modulation sources can target multiple parameters and, yes, modulation sources can target other modulation sources (although, obviously, not themselves!). There’s bags of potential here and, thankfully, it’s easily realised — the GUI makes the whole process of selecting modulation sources, adjusting their individual characteristics, and linking sources to targets wonderfully intuitive. Polyverse really have done a great job here.

Configuration of a target parameter to follow a modulation source is all done graphically.A simple drop‑down menu allows you to select a modulation source type for each of the eight slots. The slots themselves use a fixed colour‑coding (slot 1 is always red, slot 2 is always orange, and so on) and, as we’ll see, this helps you keep track of which modulation sources are linked to which target parameters. By default, a compact control layout is available across all slots, but clicking on the horizontal dots at the base of a specific slot provides a wider view that allows access to any additional settings.

There’s an impressive level of control here across all the modulation source types. The most straightforward is the ADSR envelope, but the sequencer/LFO envelope has plenty to offer, with manual or tempo sync options, a useful selection of preset curves/step patterns, variable step counts up to 16 steps, options to shape the transitions between steps, and swing. You can, of course, create your own modulation curves/step sequences. I’ve always been a fan of envelope followers, and Filterverse’s is easy to configure and very effective. It’s a great choice for letting your audio signal’s dynamics drive the modulation on one or more filter parameters, and the Attack and Release controls here allow for some interesting options when used on sounds with obvious transients. Other modulators, for example the Pitch Detect, Random and Oscillator, perhaps require a little more experimentation but they undoubtedly present some intriguing possibilities to be explored.

Once you’ve configured one or more of the modulation slots, clicking on any of the small modulation icons (towards the base of almost every parameter) pops open a panel letting you link any of the modulation sources to that parameter and to set the modulation strength and direction (positive or negative). It’s here that the colour‑coding comes in handy and, once a parameter has an active modulation link, the modulation icon changes to display the active modulation colours. Yes, it’s rather a compact icon, but it’s a helpful touch.

Kid In An Ear Candy Shop

Clicking on the preset name in the bottom strip switches the lower half of the display to the preset browser, which is nicely done. There’s tag‑based searching options on the left, and presets identified by any tag selection shown in the rest of the window. You can create your own presets, identify favourite presets and create additional tags, so it’s easy to keep your growing preset collection organised.

The supplied presets are well worth exploring. Indeed, on first use with a couple of basic sound sources (a dull synth pad and a basic drum loop), I was smiling within a couple of minutes before losing myself in ear candy land for a couple of hours! In short, all that sound‑design potential suggested by the technical features that I outlined above very quickly becomes a rather wonderful reality: put simply, Filterverse is awesome!

It can work wonders on almost any pad‑style synth sound, whether that’s simply adding more interesting tonal movement, or transforming it into a cool rhythmic element.

This is the kind of creative sound transformation that can make almost any sound the star of your mix. As you might expect, it can work wonders on almost any pad‑style synth sound, whether that’s simply adding more interesting tonal movement, or transforming it into a cool rhythmic element. It’s also brilliant on electronic or acoustic drum parts, either for transforming the sounds themselves or, thanks to the various ‘non‑filter’ reverb or delay effects, adding all sorts of rhythmic interest. Two levels of dry/wet (global or on a per‑filter basis) let you easily dial the processing from subtle to ‘notice me!’.

I’ve provided a few audio examples on the SOS website (https://sosm.ag/polyverse-filterverse) to illustrate some of the possibilities but, if you work in electronic music, pop, modern metal or modern film/TV soundtracks, all of which embrace the kinds of processed sound elements that Filterverse can so easily deliver, you could get value from the plug‑in even if all you did was tweak the presets. However, if you are happy to go DIY, there’s an almost endless set of creative opportunities to explore and, thankfully, the design and GUI make this both fun to do and relatively straightforward.

This Be The Filterverse

There’s so much to explore here that it’s difficult to shine a light on every corner of the Filterverse universe in a review, but I ought to at least mention some of the other intriguing elements that lurk beneath the hood.

For example, you’ll find Mid‑Sides processing options. Both the Meta Knob and Random Generator modulators offer musical scale‑based quantise too — if you want your filter frequency to ‘scale snap’, it’s easily achieved. Presets can be changed using MIDI CC 119 or a MIDI note, and the latter is particularly fun to explore because you can customise the MIDI note associated with any preset, effectively creating a set of keyswitches, and then from a suitable MIDI track you can trigger (or sequence) preset changes in real time. Preset changing seems instant, and while you do need to be mindful of the level changes that different processing chains might generate (and tweak the in/out settings accordingly), this is a fabulous way to ‘play’ with Filerverse’s creative potential, whether in a studio or live context.

Filterverse ships with some impressive presets to demonstrate its capabilities.

It’s also worth noting that you can adjust Filterverse’s ‘CPU/Quality’. There are low, mid, and high settings — it defaults to mid, which certainly sounded great on my host system. Cubase reported only 0.2ms latency due to a Filterverse instance, so whatever processing is going on inside the plug‑in, Polyverse appear to have made it very efficient.

Filter Tips

Although Polyverse have done a fabulous job in terms of the user experience, there’s a lot to take in when you get started with Filterverse. Fortunately, both the PDF manual I mentioned above and Polyverse’s website are well populated with useful ideas, background and tips to help you along the learning curve. While I’d still consider myself to be on the lower slopes of that curve, I’ve thoroughly enjoyed my time with Filterverse, and if I were to offer one tip of my own it would simply be to download and explore the time‑limited demo. There may be plenty of alternative contenders in the creative filter plug‑in marketplace, but if you want a single plug‑in that offers a whole universe of filter and modulation options, Polyverse’s Filterverse is very hard to beat. If you like to get creative with the sounds in your projects, you really should check it out. What a great sound‑design tool!