MuSeA

Play a track and a city appears.

This isn't a drawing that bounces to the beat. MuSeA listens to the whole track first: it pulls apart what is playing, finds the notes, and builds a city where every instrument is a building and every note a window lighting up. Then it plays the track back, and the city moves because the music that built it is being played.

One building per instrumentShape and height come out of the analysis, not from a preset. Two different tracks give you two different cities.

Your music goes nowhereThe analysis runs entirely inside your Mac. No account, no cloud, nothing to upload.

Built for a big screenMac only, on purpose: on a phone you don't see a city, you see a smudge of light.

Free, with nothing insideNo ads, no purchases, no paid tier hiding somewhere. Download it and it works.

Three different cities, not three filters

Each scene moves eight values at once — atmosphere, glow, haze, floor reflection, grain, aberration, orbit and distance — so it doesn't change the colour: it changes the place.

Neon ClubSmall-hours blue, wet reflections on the ground and film grain. The house one.

LaserClean air and the camera further back: you see the whole city and colours split at the edges.

VIP GoldThick haze, slow orbit and plenty of grain. Less city, more atmosphere.

And if you want, you drive it

The Deluxe Studio panel puts all eight controls within reach. You don't need to touch them — the scenes are finished places already — but they're there for anyone who enjoys the fine-tuning.

Atmosphere — how much light hangs in the air
Glow — the halo around each lit window
Haze — how much the background is swallowed in the distance
Reflection — the mirror on the floor, from dry to wet
Grain — film texture over the whole image
Aberration — how far colour splits at the edges
Orbit — how fast the camera circles
Distance — from street level to a bird's-eye view

Installing it

Download the .dmg using the button above.
Open it and drag MuSeA into your Applications folder.
Open it. The first time, macOS will ask whether you're sure — the ordinary prompt for any app downloaded from the internet. Click Open.

The app is signed with my developer certificate and notarised by Apple, so macOS recognises it and you won't see the "cannot be opened because it is from an unidentified developer" warning. If you do see it, the download was truncated: delete it and download again.

🔧 For the curious: how the city gets builtAudio analysis, hand-rolled 3D projection, and why there's no 3D engine — only if you fancy going deeper▾

MuSeA started life as a Python script. The Mac version keeps that analysis engine and wraps a real app around it, rather than rewriting from scratch something that already worked well.

The analysis stays separate, deliberately. A bundled Python executable — librosa inside — analyses the track and serves the result over HTTP on your own machine. The Swift app launches it, waits, and asks it questions. Porting that analysis to Swift would have taken months; this way the app existed in an afternoon.

No 3D engine. The city is a 2D canvas with the perspective projection written by hand and buildings painted far to near. A real engine would have dragged in gigabytes of dependencies to draw boxes with windows.

The haze mustn't swallow the music. The first version with haze looked beautiful and seemed deaf: the veil compressed each note's flash until you could no longer read the rhythm. Now notes burn through the haze — they subtract up to 80% of its density — and you can see it being played again.

The glow had a frame. The bloom blur leaned on the edge of the canvas and drew a line of light around the screen. The fix is clearing three pixels off each side before blurring — the kind of detail you can't see until you can, and then can't unsee.

Notarising hundreds of binaries. The bundled Python is around 250 executable files. Apple requires every one of them signed individually, inside out, and requires the app to declare that it compiles code at runtime — numba does — or the analysis dies on first use.

PlatformmacOS 14+ · Apple Silicon

InterfaceAppKit + WKWebView

Rendering2D canvas · own projection

Analysislibrosa, locally

DistributionNotarised DMG

PriceFree

Play a track and a city appears.

Three different cities, not three filters

And if you want, you drive it

Installing it

On screen