ON RESONANCE

IThe proposition

There is a moment, an hour or so in, when you stop trying to make 0 do something and start listening to what it is already doing. Everyone who plays it describes the same threshold. Before it, the instrument is frustrating — it will not go where you push it, it does not hold still, and the sound you liked five minutes ago is gone and is not coming back. After it, the frustration turns out to have been the instrument working.

0 is eight resonators arranged on an octagon, coupled in pairs, feeding a network of eight delay lines that mix through a reflection, and feeding back again. It generates nothing. Energy enters when you touch the surface and when the room makes a noise, and from then on it is only moved, delayed and lost. What you hear is a standing wave you are holding in place with your hands, and it stops when you stop putting energy in — several minutes after you stop putting energy in, which is a different thing.

It runs in a browser tab. It costs nothing. It remembers nothing at all: no presets, no autosave, no account, not even a count of how many people have opened it. When you close the tab the sound is gone, and the only way to keep it is to have been recording, which is why nine channels of audio leave for your DAW and why that is not an afterthought.

An instrument that resists you is worthless if only a few hundred people can afford to be resisted.

This essay is the argument behind those decisions. It is here because a project that publishes a list of things it will not do owes people the reasoning, and because the reasoning is more interesting than the list.

IIWhat stands between you and the sound

A violin has four strings and a piece of shaped wood, and people give it forty years. A modern software synthesizer has more parameters than a person can hold in mind, and most of them are abandoned within a season. That asymmetry is not about nostalgia, and it is not because the old thing is better made. It is about how many machines sit between the player's body and the thing that is actually vibrating.

On a violin, the answer is none. Your finger changes the length of a vibrating string; your bow puts energy into it and takes it out again continuously; the resistance you feel in your right hand is the string's own behaviour arriving back at you. There is no interpretation layer. The instrument is not deciding anything on your behalf.

On most synthesizers the chain is long. A key closes a switch. The switch generates a message. The message is interpreted by an envelope generator whose shape you set earlier, in a menu, on a different day. The envelope opens an amplifier. Somewhere upstream an oscillator has been running the whole time regardless of you. Between deciding to make a sound and the sound existing, you have delegated every meaningful choice to machinery you configured in advance. You are not playing. You are selecting which pre-arranged behaviour to trigger.

This is not an argument against complexity. It is an argument about where the complexity sits. A violin is enormously complex; all of that complexity is in the physics, immediately available to the hand, and none of it is in a settings page. The failure mode of modern instrument design is complexity that has been moved out of the player's hands and into a configuration the player must complete before anything happens.

The consequence is that 0 has six controls and no menu. Not six because six is elegant, but because six continuous parameters is roughly the most a person can hold in their attention while listening rather than looking. Everything that could not earn a word was folded into something that could, or cut.

IIIWhat we took, and what we refused to take

The argument in the previous section is not ours. It belongs, in its clearest modern form, to Vlad Kreimer of SOMA Laboratory, who has spent a decade building instruments on the premise that every machine placed between the player's body and the tone generator is a loss rather than a feature — and who points out, correctly, that the most direct electronic instrument ever built was also the first one, in 1920, and that a century of progress has mostly been spent adding distance.

We took that argument entirely. We also took the practice that goes with it: instruments whose noise floor is a design decision rather than a defect, whose tuning is something you do by ear rather than something the machine guarantees, and whose manuals are essays because the thing being explained is not a feature list.

We refused two things that came attached to it.

The first is price. An instrument built on the belief that difficulty produces attention, sold for more than most working musicians earn in a month, has quietly narrowed the argument to people who can afford to be argued with. That is not hypocrisy — hand-built analogue electronics cost what they cost — but it is a real limit, and the limit is dissolved entirely by building the thing in software and giving it away. Whatever else is true of 0, nobody is excluded from it by money.

The second is opacity. A design philosophy that insists the topology is the invention, and then keeps the topology in the workshop, is asking to be taken on trust. So the full signal path, the filter type, the five ratio sets and the exact reverb matrix are published on this site, on the day of release, in full, alongside the source. Anyone who wants to build a better 0 has everything they need to start this afternoon. That is not generosity. It is the only position consistent with the claim that the ideas are what matter.

If the topology is the invention, then publishing it is the only honest thing to do with it.

IVResonance, and what Tesla is doing here

Nikola Tesla spent his later life convinced that energy, frequency and vibration were the terms in which the universe would eventually be described, and rather less of it producing evidence for the grander versions of that conviction. He is invoked constantly by people selling things, and almost always dishonestly. So it is worth being exact about what he is doing on this page.

He is here for one specific, defensible idea: that a system driven at a frequency it prefers responds enormously out of proportion to the energy you put in. That is not mysticism, it is mechanical resonance, and it is the single most useful fact in instrument design. A small, well-placed input into a high-Q system produces an enormous output. This is why a violin body is shaped the way it is, why a room has notes it likes, and why 0 is built out of filters pushed to the edge of self-oscillation rather than oscillators pushed through filters.

He is also here for a habit of mind. Tesla thought in terms of systems that store and return energy rather than systems that consume it — circuits where the interesting behaviour lives in what circulates rather than what is generated. That is exactly the architecture of a feedback delay network, and it is exactly the architecture of this instrument.

Energy is conserved in 0 in the ordinary way, and lost in the ordinary way. The reflection at the centre of the reverb is mathematically lossless; the damping filters in the feedback paths are what make the tail end. Nothing anywhere in the system produces more than it was given. That constraint is not a limitation we work around. It is the idea.

VA geometry must produce the numbers

Geometry and music have been entangled since someone noticed that a string stopped at half its length sounds an octave higher, and that the ratios which sound consonant are the ratios that are simple. Everything since — the Pythagorean tetractys, the harmonic series, the whole apparatus of Western tuning and most of the non-Western ones too — is a working out of that observation. It is not mystical. It is the most concrete fact in the field.

It is also the single most abused idea in instrument marketing. "Sacred geometry" usually means a picture of a flower of life on a splash screen and nothing whatsoever in the audio path. So 0 holds one rule, and it is enforced ruthlessly:

A geometry is only in this instrument if it produces the numbers. If it is decoration, it does not go in.

The interface is a regular octagon, because there are eight resonators and eight is what you get when you halve four. An octagon has, from any vertex, four distinct chord lengths — 2R·sin(kπ/8) for k from one to four. Those four numbers, and their octaves, are a tuning. It happens to be a beautiful one: mirror-symmetric, slightly wide of anything tempered, and unmistakably not a scale anyone has used before. The interface was always a ratio table. It had simply never been asked for its numbers.

The HARMONIC control sweeps continuously through five such sets, interpolating in the logarithmic domain so the tunings between them stay musical rather than passing through arithmetic mush. Nothing snaps and nothing is labelled on the dial.

The tetractys is the 2·3 lattice — every ratio a product of twos and threes, which is Pythagorean tuning stated as a shape. The vesica gives 1 : √3 : 2, the triangle inside two overlapping circles, continued in octaves. Phi stretches the series by the golden ratio, producing partials that never coincide and therefore never quite fuse into a single tone. Each of these is a figure you could draw. Each of them, here, is eight numbers that determine eight frequencies.

On the surface, as HARMONIC moves, the octagram's chords light up as their ratios engage — the figure visibly changes which of its own lines are alive. That is not an animation loosely inspired by the sound. It is a readout of the tuning.

VIThe reflection

Here is the part that made the whole project cohere, and it arrived as a genuine surprise rather than a design decision.

A reverb of the kind used in serious work is a feedback delay network: a set of delay lines whose outputs are mixed together and fed back into their inputs. The quality of such a reverb depends almost entirely on the matrix that does the mixing. If the matrix is arbitrary, energy accumulates in some directions and drains from others, and the tail rings, or booms, or dies unevenly. What you want is a matrix that redistributes energy without creating or destroying any — which is to say, an orthogonal matrix.

The standard choice, and ours, is a Householder reflection:

So: eight resonators standing on the vertices of an octagon, and eight delay lines mixing through a reflection in eight-space. The geometry of the figure and the geometry of the reverb are the same mathematics, arrived at from two completely different directions — one from wanting the interface to be a shape a person can read, the other from wanting the reverb tail not to ring.

Nothing about that needs to be exaggerated, and it would be much less interesting if it did. This is the difference between a project that uses geometry and a project that is made of it: we did not choose the Householder matrix because it was symbolically appropriate. We chose it because it is the correct engineering answer, and then noticed what it was.

VIISpace is the instrument

In most music software, reverb is the last thing in the chain and the last thing anyone thinks about — a wash applied to a finished sound to place it somewhere. In 0 it is a voice. The space engine feeds back into the coupling matrix, which means the resonators are excited partly by their own reflections, which means the room the sound is in is also one of the things making the sound.

This has a practical consequence and a philosophical one. Practically, it means FORM — the control that scales the whole space engine — is not a wet/dry knob. Turning it up does not add more of an effect; it changes what the instrument is. At the bottom of its range you have eight resonators in a small hard box. At the top you have a decay measured in minutes, a diffusion field dense enough that individual events stop being locatable, and grains harvested out of the delay memory and replayed at pitches drawn from the current ratio set, so the instrument is playing its own past back into its present.

Philosophically, it means the composition happens in the tail. A gesture that takes half a second to make is still audible four minutes later, transformed by everything that has happened to it since. You are not playing notes into a space; you are managing the contents of a space over time, adding to it occasionally, listening to it constantly.

VIIIThe settling

0 has a meditative aspect, and it has no meditation mode. Those two facts are connected.

A mode would be a menu, and there are no menus. A timer would be a number counting, and there is nothing counting anywhere in this instrument. A guided anything would be a machine telling a person how to pay attention, which is the opposite of what an instrument is for. What is left, once you have refused all of that, is to build something whose behaviour rewards stillness and then say nothing about it.

So: lifting your hands does not stop the sound. There is nothing to hold down, no note-off, and no sense in which you have to keep playing to keep it alive. Letting go is a musical act with a result, not a pause.

And then the strange one, which is the most deliberate decision in the whole design. The longer the surface goes untouched, the higher the resonators' Q drifts — over about six minutes, roughly doubling. The instrument becomes more sustained, more singing, more itself, the longer you leave it alone. It resets, slowly, when you touch it again.

Every synthesizer ever built rewards input. This one rewards you for stopping.

The first person to encounter that will think it is broken, and they will be both right and wrong. It is a deliberate inversion of the reward structure that every interactive object made in the last twenty years shares — the assumption that engagement is the thing to maximise and that a system should be at its most interesting exactly when you are touching it. That assumption has produced a great deal of software that is difficult to put down and very little that is worth sitting with.

Around it sit four quieter behaviours. The microphone, which already listens to the room to find the note it prefers, also picks up a very slow envelope in the region of a tenth of a hertz — in a quiet room, largely the breathing of whoever is in it — and that envelope opens and closes the diffusion, so the space breathes at roughly the rate the room does. Nothing is recorded and nothing leaves the tab; it is a modulation source, exactly like the room's fundamental, and it is not biofeedback and will never be described as such.

The outer ring of the mark makes one revolution in twenty minutes: slow enough that you cannot watch it move, fast enough that you notice it has. It is the only motion on the page that is not sound, and it is the only acknowledgement anywhere that time is passing. There is no clock.

Left alone, the interface dims over four minutes until only the arc rings and the brass core remain, and the screen becomes closer to a candle than a display. Any contact restores it completely and immediately; nothing is ever hidden, only quietened.

And silence is a state rather than an off. With ESSENCE fully down the resonators sit below oscillation with the network still circulating and the room still coupled in, so the instrument is audibly present at the edge of nothing. You can play the approach to silence, which is most of what this kind of listening consists of.

One sentence governs all of it, and it is in the constitution so that nobody can quietly drop it later: 0 is an instrument that rewards stillness. It is not therapy, not treatment, and not a wellness product, and the copy will never imply otherwise. A good long tail is a good long tail. That is enough to be worth building.

IXWhy nothing is kept

0 stores nothing. No presets, no autosave, no recall, no history, no undo. Close the tab and the state is gone permanently. This is the refusal people push back on hardest, and the reasoning has two halves.

The first half is about what a preset does to playing. A preset is a decision made on a previous day, by a previous version of you, in a different room, and loading one begins the session with an act of selection rather than an act of listening. Instruments that cannot be recalled are approached differently: you arrive at a sound by ear, because there is no other way to arrive at one, and the arriving is most of the work. This costs you something real — you cannot return to yesterday's sound, ever — and we say so rather than dressing it up.

The second half is about what storage does to a piece of software. Once an application keeps state, it wants an account to attach the state to. Once it has an account, it wants to know who you are. Once it knows who you are, there is a reason to count you, and once there is a counter there is a metric, and once there is a metric there is a pressure on the design to move it. Almost every unpleasant property of modern software is downstream of the decision to remember things about people. 0 declines at the first step, which is the cheapest place to decline.

There is also a WAV writer, which streams straight to a file you have chosen, sample by sample, as you play. Even there 0 holds nothing: the disk does. It is a small distinction and it is the whole design in miniature.

XWhy it is free

Not free as a trial, a tier, or an acquisition strategy. Free because the argument this instrument makes is an argument about attention, and an argument about attention that only reaches people with disposable income is a much smaller argument than it thinks it is.

There is no price, no pro version, no unlock, no upgrade, and no donation prompt while you are playing. There is no counter, so we will never know how many people have used it — which is a real cost, cheerfully paid, because the alternative is a number that would start to matter.

Four things can be checked rather than believed. The schematic is published on release day, not on request. The source is open. The whole instrument runs offline after the first load. And if sonic.org.uk is ever shut down, the final build stays downloadable and playable without us — the thing outliving the organisation is a design requirement, not a promise.

XIWhat we are not claiming

A project that borrows Tesla's register, arranges itself on sacred figures and talks about stillness is one short step from a great deal of nonsense, and the step is easy to take by accident. So, plainly, and in one place:

The ratios in section V are figures with numbers in them. The numbers make good sound. They are not sacred, not ancient, not healing and not true, and nothing follows from their history except that other people also found them interesting. The reflection in section VI is ordinary linear algebra that happens to be beautiful. The breath coupling in section VIII is a slow envelope band used as a modulation source; it does nothing to your body and measures nothing about you. Resonance is a mechanism. Everything we say about what it means is offered as meaning, and marked as such.

We hold one rule above the others: no claim we cannot show you the code for. It is the reason the schematic is published, the reason the source is open, and the reason this section exists at all. If any sentence anywhere on this site crosses that line, it is a mistake and we would like to be told.