Torso Electronics S-4

Torso’s ambitious ‘sculpting sampler’ may be a work in progress, but it promises to be something very special indeed.

Torso Electronics are a young Danish company with a preference for user interfaces that minimise the gap between ideas and realisation. Their first product, the T‑1 sequencer, has the hands‑on directness of a performance instrument and for their second, the S‑4, a similar philosophy is applied to audio capture and processing.

The S‑4 is described, rather mysteriously, as a ‘sculpting sampler’. Our mission today is to discover what that means — and then try to decide if it’s a creation worthy of Michelangelo, or the product of just another bloke with a chisel...

So What Is It?

Listing the current functionality feels like a safe enough way to kick off. S‑4 workflow is based upon four stereo tracks, each of which can act as a virtual tape recorder, a polyphonic sample player or a gateway for incoming audio. The tracks are then subjected to a series of ‘sculpting’ options — currently a granular effect, a morphing resonator, several flavours of distortion and a combined reverb and delay. Additionally, the S‑4 can act as a USB audio interface — one that’s capable of expanding its I/O automatically whenever a class‑compliant device with extra channels is attached. Lastly, for instant results in any environment, it features a built‑in microphone.

Onboard storage (4GB) is provided for samples and projects, plus there’s a USB‑C connector to enable file transfer from a PC, Mac or peripherals such as external drives. Arguably, the only omission is an SD card slot, or a similar means of boosting the storage unobtrusively, because, if my experiments are anything to go by, that 4GB will fill up pretty darn quickly.

Internally the S‑4 sports a — now ubiquitous — Raspberry Pi with a quad‑core 1.5GHz processor. Audio is a clean 24‑bit, 48kHz throughout and, while the stereo audio inputs and outputs are on quarter‑inch jacks, all the other connections are 3.5mm, including the headphone socket, MIDI in and out, plus the analogue clock I/O. A single adaptor (Type A) is supplied to turn mini‑jack MIDI into the regular five‑pin type and the power adaptor ships with a selection of country options; you can pack them away in readiness for those sunlit days when touring is viable once more.

On the rear panel we find 3.5mm sockets for headphones and MIDI and sync I/O, quarter‑inch sockets for audio I/O, a USB‑C port and power supply input.

As hardware devices go, it’s a petite package measuring a mere 156 x 242mm and standing just 39mm from its rubbery feet to the tips of its encoders. The RGB buttons are chunky‑feeling and those encoders map to objects on the 3.5‑inch pin‑sharp LCD in ways Elektron users will instantly recognise. Admittedly, the encoders don’t handle quite as nicely as those of an Elektron but my main misgiving is their black on black aesthetic — this design choice feels needlessly obtuse, at least in my darkened studio. That said, my fingers eventually learned their way around without troubling my brain too much.

Sculpting Time

On power‑up you’re greeted by an empty project and so immediately have choices to make — such as what role(s) the S‑4 should perform today. Hopefully in some future update there will be an option to start from your own defaults, or from where you left off previously, but for now you must either load a project manually or begin with Torso’s preferred settings. Incidentally, stored projects appear in a simple list, sorted alphabetically — and it’s not hard to predict this will soon become long and unwieldy.

Beneath the encoders are buttons representing the chain of audio devices available. From left to right, these are: Material, Granular, Filter, Color and Space. All can be bypassed if necessary but, at present, Material is the only one to offer multiple modes — Tape or Poly. When Material is bypassed, that track is ready to receive incoming audio.

The S‑4 boots as a virtual four‑track tape machine with an interface that’s so friendly it invites you to begin recording and overdubbing right away. However, you quickly realise there’s no indication of how long you’ve been going — or how much time you’ve got left. Further investigation revealed that a maximum of six minutes is allocated per track, but some kind of time or bar counter visible during recording would be very much appreciated.

Recordings are based on a global tempo value — either sourced internally or taken from your selected input (MIDI or analogue). Synchronisation arrived quite late (version 1.1) with further improvements and hotfixes following in 1.2.x. It’s perfectly straightforward to adjust the start and end of each reel on the fly, shift the audio relative to other tracks or chop to precise bar intervals when a perfectly sync’ed loop is required. That said, I’d love to see a zoom function implemented so you could more easily fine‑tune those starts and ends when not working to bar/beat divisions.

Actually, it’s worth a quick mention of the way units are employed throughout the S‑4, because it’s rather neatly done and superior to most audio looping/recording devices I’ve used. For any Tape track, pressing and turning the Tempo encoder presents you with a selection of either Sync, Free or Stretch modes. Sync locks you to the current bpm and all parameters duly reflect this (in beats and bars). Free, on the other hand, acts more like a regular tape recording, with the units for start and recorded length specified in seconds. Finally, Stretch is unique to Tape tracks; it separates pitch and time, instantly lending itself to more granular applications.

Unusually, you can override the speed and tempo at track level, but the implementation is not without its peculiarities. For example, and counterintuitively, if you increase the track’s tempo while bpm‑sync’ed, the pitch drops (and vice versa). Still, with speed modifications of up to three times (faster or slower) and options such as scale quantisation, freeze and reverse playback, there are oodles of ways to interact with those virtual reels.

A second press of the Material button reveals yet more parameters — Glide, Density, Level and SOS. Glide smooths the transition between tape speed changes, while Level is handy for boosting a recording once it’s been laid down. This is especially important because there’s no gain control provided for the line inputs — hopefully another something to be added when time permits. SOS determines the amount of existing signal retained when overdubbing, so vital for tape loops you want to fade gradually on each pass. And, as you’d expect, dropping out of overdub at any time maintains the current level.

When in Stretch mode, Tape reveals its underlying granular nature with the Density parameter controlling both grain size and rate. If you engage Freeze and play around with density, shift and pitch, many happy hours may be lost disrupting the fabric of reality.

With four tracks to play with, the Track button is a helpful entry point for selection and for checking which audio devices are currently enabled. It also contains four individual send levels, used to pipe the current track’s output into any of the others, or back into itself. This is a rare level of connectivity and brimming with routing possibilities, some of which we’ll consider later.

The S‑4 measures 242 x 156 x 39mm and weighs 820g.

Modulation

Before moving on, I should point out the Mod button which, if you’re as loose‑fingered as I am, you might have already brushed accidentally. Modulation is a simple four‑slot affair, colour‑coded on the display for ease of recognition and offering Random, LFO or an ADSR envelope (manually or MIDI‑triggered) as potential sources. In use, this is an elegant means of adding movement to parameters on any page; as an extra bonus, the display gives real‑time updates of the modulation in action. The main omission is some form of envelope follower to harness the contours of incoming audio but, according to a recently published roadmap, this is on the cards for the next major update (1.3).

Each modulator is loaded with numerous options to skew, smooth or distort its basic shape and there’s a choice between sync’ed and unsync’ed rates. On the rare occasions when the sources provided are insufficient, you’ll be pleased to know that the S‑4’s parameters can be controlled remotely by MIDI CCs and note numbers. The power to toggle record and overdub states using notes (eg. fired in from a sequencer) is a major highlight, not least because it eliminates the guesswork from loop creation.

The temptation to modulate pretty much every parameter on every page can be almost irresistible, at least at first, so it’s a relief to discover the Clear button. It’s there to instantly wipe every amount, value tweak and even the audio buffer itself.

Sample Playback

If you switch Material from Tape to Poly, your tape recording can be played like a regular sampler, with up to eight notes of polyphony. Oddly, sampling isn’t possible in this mode but at least samples can be loaded from the onboard storage or from a peripheral device hanging off the USB port. Some examples are provided — instruments, percussion, sound effects and so on — but I’d be tempted to wipe the lot and replace them with my own, especially as there’s no audition function! Basically, unless you know which sample you want in advance, let’s just say the process can be rather laborious.

While in Poly mode, you lose the tape‑specific parameters and the waveform graphic is compressed to make room for a simple envelope. This envelope is shared by both output and filter but there are offsets so the two needn’t be identical. However, decay and release are combined into a single parameter, plus there’s no multisampling or slicing. Right now, it’s fair to say that Poly mode falls a little short of what you might expect from a sampler but, in its favour, you’ve got up to four stereo samples, each on a unique MIDI channel and ready for further processing.

Granular

Mosaic is a granular processor that includes pitch‑shifting (of up to 36 semitones either way) and a grain spawn rate that can either run freely or lock to tempo. Most of the processors feature a wet/dry mix and this is particularly welcome here because you can bring in the granular effect smoothly after you’ve set all its parameters to taste. Alternatively, you can control the mix with an LFO, envelope or MIDI CC.

Up to 128 grains can be generated, panned around the audio spectrum and even quantised — to a collection of scales that go way beyond the more commonly found octaves and fifths. Furthermore, a set of built‑in patterns act as a quickly summoned means of modulating the grains’ pitches, again limited by the current scale.

Granted, the four‑second buffer and limited control over grain shape won’t trouble dedicated granular synths such as the Tasty Electronics GR‑1 or GR‑Mega, but Mosaic is capable of many cool transformations all the same. Most importantly, it handles with a minimum of fuss; for example, on its second page are options to randomise the grain size, rate and detune, all set up and ready to deploy without any need to delve into the Mod section.

Filter

Next along the audio chain is Ring, a morphing resonator consisting of a 48‑band tuned filter bank, plus regular filter functionality with variable slope and tone. The filter will morph smoothly through low‑pass, band‑pass and high‑pass modes and when you turn up the decay, this causes the various bands to ring out in a distinctive and instantly recognisable manner. Once again, pitch‑shifting and quantise to scale are on hand to precisely tune the output.

For added control, you can apply regular filtering before or after the filter bank and apply modulation to chop, slice and sweep the cutoff — or simply blend the original and filtered audio. So while this isn’t the most analogue‑sounding filter you’ll ever hear, with just a bit of thoughtful tweaking it can extract magic from pretty much any input. And, as I was starting to expect, the graphics do a splendid job of keeping you informed. Anyone partial to mesmerising visualisations of audio being massaged might find themselves lingering here for a long time.

Colour

Next down the line is Deform, the S‑4’s device for adding dirt, compression, bit‑crushing and noise. Basically all the nasties you might have preferred before the filter. Actually, there is a way to achieve that too, but, for the moment, it’s worth noting Deform as a gritty two‑channel tonal modifier. Its Tilt parameter serves as a balance between low and high colorations and, like many of these effects, responds well to small amounts of modulation.

Personally, as a lover of dreamy ambient soundscapes, I rarely distort or crush them, but if your tastes lean towards the industrial or experimental, Deform is for you. It also scores highly for adding bite and aggression to Poly mode samples, particularly percussion.

Space

Finally, Vast is a combined delay and reverb that’s ready to smudge and blur those warped and broken sounds. Admittedly, it is not the warmest, lushest hall reverb nor the most flexible delay, but both are serviceable enough in context. And when you begin to wobble a few parameters with an LFO, Vast becomes far more interesting.

Here, each amount is not a send control but is actually a balance, so when you crank it up for either delay or reverb, you’ll typically need to reduce the default damping level or experience a palpable loss in energy.

Fortunately, there is another way to approach this, and for that we’ll return briefly to the Track page and its send controls. Instead of using Vast on every track, you might prefer to reserve just one for global delay or reverb duties. To do this, simply bypass every device but Vast, then set either reverb or delay to full‑on. After that you can feed in the other tracks as required from the Track page. This technique could also be adapted to achieve filtering post‑distortion, if you hadn’t already guessed.

Last but not least, a master mixer is available, featuring level and pan for each track, plus a quick but effective DJ filter — high‑pass and low‑pass in a single control. While no substitute for a full EQ section, it’s ideal for quickly sorting out unruly top or bottom ends. A simple compressor resides here too and, thanks to those friendly modulators (or MIDI remote control), automated mixing need never be more than a few button presses away. Should you wish, you can record a master mix directly from this page, even if all four tracks are already in use.

The S‑4 is a real‑time audio playground in which looping tape recorders, sample players and quirky effects processors compete for attention.

The State of Play

The S‑4 is a real‑time audio playground in which looping tape recorders, sample players and quirky effects processors compete for attention. Thanks to a well thought‑out user interface, its four tracks provide instant gratification and flexibility in equal measures. However, there’s no avoiding the fact that this is a work in progress — and has been for some time already. I don’t want to trivialise the challenges faced by small companies in these trying times, but with some aspects tantalisingly unfinished and four non‑functioning buttons (Copy, Scene, Perform and Temp) it’s hard to completely banish the fear that human civilisation might throw in the towel before we learn what they’re for.

Fortunately, there’s plenty to enjoy as things stand today, not least its seemingly endless capacity for evolving textural wonders. With up to six minutes per track and numerous options for warping and overdubbing, Tape mode can be anything from a regular looper to a complete ambience factory. Switch to Poly mode and you get a basic but functional sample player; or, as a third option, you can simply give some of your gear the benefit of those carefully‑crafted processors.

Despite some glitches along the way, including several weeks in which I couldn’t load any projects, I’ve relished my time with the S‑4. Indeed, it has carved out a place in my workflow (and affection) that would be impossible to replace with anything else. Although there are some overlaps with gear such as the 1010music Blackbox and Roland RC‑505, the S‑4’s trippy, freaky nature sets it apart.

To reach a definitive conclusion still feels premature, but for those willing to risk a bit of adventure, the S‑4 might lead you in directions you never considered before, or even knew existed. I’m looking forward to what comes next.