Skylines, played
A skyline and a spectrum analyser are the same picture. So the picture is played.
Both are a row of vertical bars of varying height. That is a coincidence of drawing conventions rather than of physics, but it is usable: if a skyline can be read as a spectrum, it can be played, and the sound will change as the listener turns. This tool does that for twenty-seven cities, using published building heights and coordinates.
27 cities
The upper panel is a wheel of the city's towers, up to a hundred and twenty of them, with the far side drawn in a colder color because it is behind the listener. The lower panel is the same ring as a meter, and the meter is what sounds. Drag to turn, or press Spin.
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The real top eight towers of New York, by height - the same bars, read as a spectrum instead of a skyline.
What is measured and what is invented
Sonification tends to blur the line between what was observed and what was composed, so it is drawn sharply here.
Measured. Each building carries a published structural height and a published coordinate: from Wikidata for twenty-four cities, each tower linked to its record from the app; from the city's published tallest-buildings list (Wikipedia, retrieved 2026) for Austin, Nashville and Fort Worth, where Wikidata had three, fourteen and a handful of buildings on record. The order of the towers around the wheel is their true compass order from the height-weighted center of the city, and the heights on the wheel are meters.
Chosen. The listener stands at that center. A tower closer than four hundred meters is held at four hundred, so a building you are standing under does not dwarf the rest; the app writes "under 0.4 km" rather than a number for those. The wheel takes the city's tallest buildings down to fifty-five meters, at most a hundred and twenty of them; the headline count uses eighty. For the three supplemented cities the published list overrules Wikidata above the height the list says it is complete to. Every one of these floors is shown in the app's side panel.
Rearranged. The spacing around the wheel. Buildings hold their true compass order, clockwise from north; the angle between any two of them does not survive. A downtown occupies perhaps forty degrees of a real horizon, and a wheel that reproduced that would be two-thirds empty. A transit map takes the same liberty with distance, for the same reason. One consequence is worth stating plainly: there is no empty horizon on a wheel, so turning changes the chord and never silences it.
Invented. The sound, all of it. There is no sense in which a city has a pitch. The mapping is a choice, it is written out in full below, and it is deterministic: the same city at the same bearing always makes the same sound.
The key
| City | Key | From |
|---|---|---|
| New York | Bb blues | Gershwin, Rhapsody in Blue - the opening clarinet glissando arrives on B flat, and the piece was written as a portrait of the city |
| Dubai | D hijaz | maqam Hijaz, the mode most characteristic of Gulf music |
| Shenzhen | D pent major | gong mode |
| Tokyo | D yo | the yo scale, the pentatonic used in Japanese folk and much gagaku-derived music |
| Chicago | E blues | the Chicago blues, which is a named genre of the city; E is the guitar's home key and the one most of it is played in |
| Toronto | G major | O Canada, published in G major |
| Paris | C major | Edith Piaf, La Vie en rose, recorded in C major |
| Moscow | Eb major | Tchaikovsky, 1812 Overture, op. 49, in E flat major |
| Taipei | G pent minor | yu mode |
| Hong Kong | E pent minor | yu mode, as in Cantonese opera |
| Tel Aviv | D hijaz | Ahava Rabbah, the Jewish liturgical mode with the same interval structure as Hijaz |
| Seoul | G pent major | the pyeongjo mode of Korean court music, a major pentatonic |
| Austin | E blues | Stevie Ray Vaughan, whose Texas blues is the city's own sound, played in E on a guitar tuned down a half step |
| Fort Worth | C major | George Strait, Does Fort Worth Ever Cross Your Mind, recorded in C major |
| Nashville | G major | the Nashville Number System, the chord notation this city invented and still runs sessions on; G is the key its session players default to |
The thirteen with the most skyline, then Fort Worth and Nashville. Nineteen distinct keys across eight modes in all, and the eight modes are voiced eight different ways (below), so no two of the nineteen sound alike.
How the bars become sound
Every row of this table is a choice. None of it was measured, and the app says so where the sound is made.
| Property of the bar | Property of the sound | Why |
|---|---|---|
| Position across the view | Which note of the city's chord: nine to eleven notes over two and a half octaves, lowest on the left, with the root an octave down as a drone | Ninety-six bars is the right number to look at and the wrong number to play; adjacent bars on one note would be oscillators detuned by nothing, beating. A note takes the loudest bar that feeds it. |
| Height, as a share of this city's tallest | Loudness of that note, as the share to the power 1.6 | The exponent makes the peaks stand out in the ear the way they do in the picture. Normalising per city means every city's tallest tower is equally loud: Fort Worth is not quieter than New York for being shorter. |
| How many bars are lit | At most seven notes sound at once, the loudest seven | A bearing that lights every note is a chord nobody wrote. Density is most of what makes an additive tone harsh. |
| Which note it is | Higher notes are tilted quieter, by one over the square root of their index; every fourth voice is a triangle wave, the rest are sines | An instrument loses energy with height; a flat spectrum is a buzz. The triangles give the low voices a little edge. |
| Everything | A shelf pulling down 1.8 kHz and above, a low-pass at 3.2 kHz, a limiter, and a fixed ceiling | So that no city at any bearing can line up its partials in the band the ear is most sensitive in. The mapping cannot know what hurts; the instrument is built so it cannot produce it. |
Which notes of each mode sound is also a choice. Each mode is voiced on its own terms, with the tone that makes it itself placed an octave up, where it colors the chord instead of clashing with the root beside it. No two sounding notes are ever closer than a minor third.
| Mode | Lowest octave | Octaves above | Cities |
|---|---|---|---|
| major | root, third, fifth | the same | Paris, Toronto, Moscow, London, Los Angeles, Auckland, Nashville, Calgary, Vienna, Brussels, Fort Worth |
| minor | root, minor third, fifth | the same | Frankfurt, Warsaw, Miami, Rotterdam |
| hijaz | root, third, fifth | flattened second, third, fifth | Dubai, Tel Aviv, Madrid |
| pentatonic major | root, third, sixth | the same | Shenzhen, Seoul |
| yo | root, fourth, sixth | the same | Tokyo |
| pentatonic minor | root, minor third, fifth, flattened seventh | minor third, fifth, flattened seventh | Taipei, Hong Kong |
| blues | root, minor third, fifth, flattened seventh | minor third, flattened fifth, flattened seventh | New York, Chicago, Austin |
| insen | root, fourth, flattened seventh | flattened second, fourth, flattened seventh | Osaka |
The app names the notes sounding at any moment in a line under the meter, so the instrument can be read as well as heard.