Experimental · in development

Listening Observatory

An experimental system for continuous computational listening.

Listening Observatory connects to live audio streams, analyses their acoustic structure in real time, and translates what it hears into evolving visual forms and short textual observations. Rather than treating sound as something to be displayed moment by moment, it listens across timescales: from immediate frequency changes to recurring resonances, motifs, and longer patterns it remembers.

Streams

checking… VLF Natural Radio · Heidelberg Heidelberg, Germany · Very low frequency radio, analysed at 0.8–16 kHz Earth's own radio. A receiver near Heidelberg turns very low frequency radio waves into sound: the crackle of lightning strikes thousands of kilometres away (sferics), falling tones that travel along the magnetic field (whistlers), and the steady hum of the power grid. Listen → checking… VLF Natural Radio · Cumiana Cumiana, Italy (near Turin) · Very low frequency radio, analysed at 0.8–16 kHz Earth's own radio from the foot of the western Alps. Renato Romero's receiver in Cumiana, near Turin, turns very low frequency radio waves into sound: the crackle of distant lightning (sferics), falling tones that travel along the magnetic field (whistlers), and the hum of the power grid. Listen → checking… VLF Natural Radio · Pennsylvania Spring Brook Township, Pennsylvania, USA · Very low frequency radio, analysed at 0.8–16 kHz Earth's own radio from north-eastern Pennsylvania. Jonathan Rizzo's receiver near Scranton turns very low frequency radio waves into sound: the crackle of distant lightning (sferics), falling tones that travel along the magnetic field (whistlers), and the hum of the power grid. Listen → checking… Mars · InSight Elysium Planitia, Mars · Seismometer: wind, marsquakes, the lander itself Sound from the surface of Mars, heard through a seismometer. NASA's InSight lander felt the Martian wind, two marsquakes and the ticking of its own parts cooling at night; these recordings, sped up or raised in pitch to become audible, play here in a 21-minute loop. Listen → checking… Jupiter · Juno Jupiter and its moons Ganymede and Europa · Radio and plasma waves, shifted into hearing range Jupiter's radio voice. The Waves instrument on NASA's Juno spacecraft records radio and plasma waves around the planet; shifted into the range of hearing they become rising tones, whoops and crackle. A 4-minute loop from the flybys of Ganymede and Europa and from Jupiter itself. Listen →

How it listens

Observation

Signal processing measures the sound continuously: frequencies, harmonics, spectral energy, entropy, sudden transients and persistent resonances.

Memory

A memory compares what it hears with what it has heard before. Structures that recur become motifs with a persistent identity, and are recognised when they return.

Visualization

Drawn live in the browser from these observations: a landscape of the spectrum, resonances rising from it, disturbances where transients strike, and a dial of what has been remembered.

Interpretation

A language model phrases the measured facts in two short sentences. It never decides what happened in the sound: every frequency and motif it names is checked against the measurements, or the text is discarded.

The DSP system observes · the memory recognises · the visualization embodies · the language model gives words to what was measured.

How to read a live page

The landscape. The spectrum as terrain: low frequencies on the left in warm colours, high ones on the right in cool colours. Height is loudness; the rows recede into the past, the front row is now.
Resonances. Spires rise where a frequency holds steadily. The label gives its frequency and, once remembered, its motif; rings mean it has harmonics, thinner spires mark the harmonics themselves.
Transients. A sudden burst of sound sends a shockwave through the landscape.
Readout. The time at the source, the overall state (for example stable resonance or broadband noise), harmonicity, spectral entropy and novelty: how different the sound is from the last minutes.
Listen. Plays the stream in step with the picture: every event is shown when you hear it. Where a source allows it.
Interpretation. The newest text types in on this line. Scroll it (wheel, trackpad or swipe) to read earlier ones.
Memory dial. Every remembered motif is a station on a radio dial, at its frequency: taller marks were heard more often, brighter ones more recently, shaded bands are sound textures. The needle follows the dominant frequency. Point at a mark for its details.
Signal. Spectrogram of the last minute, the current spectrum with its peaks, and the harmonic map of the last five minutes, coloured by motif.
Observations. The measured features and the latest events: resonances, fades, transients, new and returning motifs.

Listening Observatory is open source (github.com/vrontier/listen). The audio belongs to its sources and is credited on each stream's page. Questions, ideas or a stream worth listening to? Get in touch.