How it works

Grid Radio is a radio station whose only artist is the Gridcoin blockchain. Every block the network stakes is compiled into a short piece of ambient music, using nothing but its hash, and put on air. This page explains the machinery: how 32 bytes become a tune, why the tune is never ugly, and why it will sound exactly the same in twenty years.

One artist, no playlist

A block hash is 32 bytes of publicly verifiable noise. It was produced by consensus, nobody chose it, nobody can predict the next one, and everybody on the network agrees on it forever. As raw material for generative music this is close to ideal: an inexhaustible, incorruptible, slightly pompous composer who publishes a new work every 90 seconds and never takes requests.

The chain has been staking blocks since 2013: several million works, all composed before this station existed. Grid Radio did not add music to the blockchain. It added a receiver.

The broadcast standard

The mapping from hash to score is a frozen pure function, versioned as gridradio:v1. Freezing it is the whole point: change one constant and every block in history changes its tune, which would make the station a liar. If the standard ever evolves, the new version activates at a block height, the way the chain versions its own consensus rules. Every block before that height keeps its v1 tune, its v1 band, and its v1 sky, forever; only blocks staked after it are compiled under the new rules.

The byte map

Every byte of the hash has a job. None are wasted, none are used twice for the same voice:

b0        key       b0 % 12 semitones above A
b1        mode      one of nine scales: five diatonic church
                    modes (the house sound), four pentatonics
b2        tempo     30 + (b2 % 61) BPM
b3        drone     detune in cents; top bit adds the fifth
b4..b19   melody    a walk on the grid: mostly stepwise, leaps
                    step back, downbeats lean on the chord,
                    the last two notes cadence home; the feel
                    (straight, syncopated, sparse, or busy)
                    from (b2+b26) % 4; b21 gates motif blocks
b16       form      3, 4, 6, or 8 bars; past bar 4 the phrase
                    answers itself, and one value in eight is
                    minimal: drone and bells only
b7,b11,…  harmony   chord roots and pace (commentary reuse);
                    melody and bass agree with the chords
b20..b27  bass      slots an octave down; steady, half-time,
                    or pushed, from (b3+b20) % 3; chord roots
                    where the harmony changes
b28..b31  bells     4 chimes, scattered anywhere on the grid
b29..b31  title     b29 picks one of six grammars, b30 the
                    adjective and its contrast class, b31 the
                    noun; verb, gerund and preposition come
                    from b8..b12 (commentary reuse)

Melody bytes also carry dynamics: the high nibble sets how hard the note is struck. Two bells landing on the same step make a chord, not a bug.

The nine scales

Byte 1 picks the score’s scale, and with it the mood the interface reports as sky conditions:

0  major pentatonic   0 2 4 7 9         "clear"
1  minor pentatonic   0 3 5 7 10        "overcast"
2  ritusen            0 2 5 7 9         "dawn"
3  hirajoshi          0 2 3 7 8         "night"
4  ionian             0 2 4 5 7 9 11    "azure"
5  dorian             0 2 3 5 7 9 10    "mist"
6  lydian             0 2 4 6 7 9 11    "aurora"
7  mixolydian         0 2 4 5 7 9 10    "amber"
8  aeolian            0 2 3 5 7 8 10    "dusk"

Two thirds of blocks sing in the seven-note church modes; a third keep the pentatonic floor. Phrygian and locrian are deliberately absent: the one fights a drone, the other has no home to cadence to.

Why no wrong notes

The guarantee has two tiers. On pentatonic blocks it comes from the scale itself: pentatonic scales contain no dissonant intervals, so any subset of their notes, in any order, at any time, is consonant. This is the oldest trick in generative music (and the reason a toddler on the black keys of a piano sounds wise rather than alarming). On diatonic blocks the scale offers no such shelter, so the rules take over: the melody plays on the chord progression. Skips and leaps may only land on tones of the chord that is sounding; dissonance is only ever passed through by step, the way tonal music has always handled it; and no move may span a tritone. The bells and the bass hold to chord tones too, so the sparse voices cannot be the ones that land wrong. Different guarantees, same promise.

Why it sings

Notes that cannot clash still cannot sing on their own. So the bytes are read as movements, not positions: the melody walks. Mostly it moves by step, the way nearly all real melodies do; when it leaps, the next note must step back the way it came, which is the oldest rule in counterpoint. On downbeats the line leans onto the tones of the chord underneath, preferring not to double the bass (thirds and sixths are where pretty lives). The highest notes only open up near the climax of the form, and the final two notes walk home to the root, so a tune ends rather than stops; in the modes that have a leading tone, that last step is the real ti-do pull pentatonic scales never had. About a fifth of blocks go further and are motif-driven: their first bar becomes a small cell that every later bar restates, shifted a degree up or down, or turned upside down. Repetition with variation is most of what composition is. Every one of these decisions still comes from the hash alone.

Track titles

The last bytes name the piece, drawing on two lists of 128 science and sky words in keeping with the network’s day job. Byte 29 picks one of six small grammars. Most blocks get a sentence, “The Solemn and Tender Observatory Listens”, or a phrase, “Coasting by the Solemn Harbor”, because a sentence is far easier to carry out of the room than a word pair. The two adjectives in a pair always come from opposite poles of the same class, so a title contrasts (“The Veiled and Clear Lagoon Widens”) rather than repeating itself.

The short forms are deliberately the rare ones. “The Ion Burns” is drawn from a pool of only 4,096, so names like it recur perhaps fifty times across the chain: the standards a station needs, the songs everyone has heard twice. The long forms draw on pools of four million, which is where the distinctiveness lives: about 55% of all blocks end up with a title no other block on the chain has, and a block that does share its name usually shares it with exactly one other. An opus number (“Iron Comet, Op. 517”) still turns up on one block in sixteen, the honest cataloguing convention for a composer several million works deep.

The performance

The score is data; the sound is your browser’s. A small Web Audio synthesizer performs each score live: a detuned drone under everything, a lead voice, a slow bass, bells on top, all through a delay and a reverb that the hash also mixes: the delay’s timing and depth vary per block (some blocks audibly echo), and the room itself ranges from tight to cavernous. Nothing is streamed: the server sends a few hundred bytes of JSON per block and your machine does the rest. Which parts are sampled and which are synthesised is not an accident. Anything that carries a tune is a real recorded instrument: all thirteen lead voices, and two of the three bells, are public-domain notes from Versilian Studios, the Versilian Community Sample Library and the open sfz libraries. The bass and the drones are synthesised instead. We tried sampling the bass three times, with a bowed double bass, then a tuba, then a double bass played pizzicato, and every one of them had too much attack. A plucked or bowed string opens with a transient sharp enough to pull your ear onto the beat, and the bottom of this music is supposed to sit still. A voice fetches its notes only when a block actually casts it, and falls back to synthesis if they never arrive, so the station cannot go silent waiting on a download. The station could still serve every listener on Earth from a Raspberry Pi.

The instruments

The hash also casts the band, deciding both who plays and what they play it on. The lead is one of thirteen, and every one of them is a real recorded instrument rather than a synthesised approximation: a harp, the felt piano (which holds two of the thirteen seats, because the second chair auditioned a sax, a trumpet, a synth and a kalimba, kept none of them, and kept only the room they were tried in: that seat plays drowned in echo and reverb while the other plays dry), a glockenspiel, a violin section, a cello section, an erhu, a marimba, a flute, a felt piano, a solo violin, a solo cello and a vibraphone. The bass is one of four voices, and all four are a real electric bass: two plucked, two sustained voices, each with a sine an octave below it for weight and a filter close to the fundamental so nothing down there can turn sharp. Two of the three bells are a real glockenspiel; the third stays synthetic because its partials are deliberately inharmonic, a gong rather than a bar, and nothing samples that. About one block in eight also tolls: a deep tubular bell, struck softly two octaves below its home, doubles the bass root once at every chord change, a buoy marking the harmony, sparse enough that each toll rings out completely before the next. The drone is built nine different ways: warm saws, airy glass, church-still organ, a dark growl, a quiet choir, a slowly breathing pulse, a hollow vowel-like formant, two tidal layers swelling against each other, or no held tone at all but a slow piano arpeggio walking the chords. Every one of them breathes: the oscillators swell against each other at rates that never line up, and their detuning drifts, so the beating itself keeps moving rather than settling into something the ear can stop hearing. About one droned block in five is performed outdoors instead, with no held tone at all: one of eighty-two field recordings carries the floor instead. There is rain and wind and forest, but also fire, frogs, a cave, a subway, and a city street at night. The hash picks which one, how loud it sits, and how far away it sounds, that last one being nothing more than how far the filter is closed. Blocks with no melody are never sent outdoors: a drone and a few bells is already the whole piece, and replacing the drone would leave nothing. The drone’s wobble rate and depth come from the hash too, so even two saws-drones move differently. Instruments also live in different registers. The glockenspiel and the erhu sit an octave up, the sax, violin section and vibraphone an octave down, the cellos two, so a change of lead moves the whole tune’s centre of gravity. Those offsets are whole octaves, always: anything else would transpose the lead into a different key from the bass. And because a block led by a glockenspiel carries far less energy than one led by a piano, a broadcast leveller trims the output so every block meets the volume you set once. It changes no note, only playback gain. And the roster itself varies: some hashes sit the bass out, some silence the bells, some drop the drone entirely and play naked in the room, and a third of them hire an arpeggist who spells out each bar’s chord. A block can arrive as a bare duo of drone and lead, or as a full house. About one block in ten dismisses the band altogether and performs as solo felt piano: the melody in the right hand, the bass line in the left, nothing else, in a room turned large and soft for the occasion. On top of that the block’s transaction count only ever adds players: three or more transactions add an octave echo shadowing the lead, four bring in soft brush-noise percussion, six or more swell a sustained chord pad. Between the roster and the layers the band runs from duo to octet, all of it still a pure function of public data, so the determinism promise is untouched.

The harmony

The hash decides whether the harmony travels, and how fast. About a third of blocks hold a single chord for the whole loop; the rest move at one of three paces: a slow two-chord vamp, a chord per bar, or a quick walk that changes every half-bar. Moving progressions always ground their first chord on the root and always leave it by their second. Chord roots are scale tones, the moves are slow glides, and the melody leans onto the chord tones as it walks, so harmony and line agree by construction. Being drawn from the hash, a block’s harmony is as permanent as its tune. The melody and bass carry their own rhythmic feels too (straight, syncopated, sparse, busy; steady, half-time, pushed), so two blocks in the same key at the same tempo can still walk entirely differently.

When a new block is staked, the station segues: at the next bar line the outgoing tune fades out, ringing tails and all, while the incoming one fades in from its own first bar. If no block arrives, the current work simply plays again; the chain is occasionally between ideas.

The long programme

“Plays again” does not mean “repeats itself.” The chain is sometimes minutes between blocks, and a short form looped verbatim through a ten-minute gap would be a broken record. So each pass through the form is a variation: the harmony, the bass and the drone hold their ground while the melody journeys: played as written, resting for a pass, lifted an octave, sequenced up a scale step, or mirrored around its opening note. The hash picks which journeys the block takes and in what order; every cycle opens as written and closes with a reprise, and once a cycle completes it comes around again a shade quieter, the tune settling into its own landscape. Every variation is a pure function of the hash and the pass number, transformed in scale-degree space with the counterpoint rules re-applied, so a varied melody still leans on the chords, still never leaps a tritone, and still cadences home. The determinism promise extends through time, not just across listeners: the fourth pass of a block sounds the same for everyone, forever.

The weather

One thing in the sound does not come from the block: the brightness. The network’s staking difficulty drives the filter on the drone: when the network works harder, the station sounds brighter. The song comes from the block; the sky comes from the chain. Neither comes from us.

The sky

Everything you see is compiled from the hash the same way the music is. Each block paints the sky its own three colors and sets its weather in motion: how crowded the mote field is, how fast it drifts, how thick the fog sits, how often a star falls. One or two signature effects ride the music (rings radiating on bass strikes, comets, orbiting satellites, aurora curtains, embers), chosen and tinted by the block. The dial the spectrum plays on is the block’s own instrument too: bars, dots, a wave, petals or needles, turning at the block’s pace in the block’s direction. And the hash decides what hangs inside the dial. About half the blocks keep a quiet void. A third hold a soft glow that breathes with the music and drifts slowly around the block’s own palette, never settling on one color. And roughly one block in eight collapses into a black hole: an event horizon, a thin photon ring, and an accretion ring that runs hot at an angle the block chose, forever. Two listeners on opposite sides of the world see byte-identical skies.

Same hash, same tune, forever

Because the mapping is frozen and pure, every block’s page is a permanent musical record. Block 1,000,000 sounded the way it sounds the moment it was staked, years before anyone listened; it will still sound that way when everyone has stopped. There is something quietly pleasing about an archive of millions of compositions in which nothing can ever be remastered.

What this is not

There is no AI here, no machine learning, and no cloud rendering. It is modular arithmetic and a browser API from 2013, the same year the chain started composing. The blockchain does not know it is making music, which puts it in the company of most great composers’ harshest critics. And nothing about this service is useful. That is not an apology.