How Sound Galaxies are built
AnimalEar turns a recording into evidence you can inspect. It listens for real sound events, follows
repeated sources over time, and turns those patterns into Waveform, Spectrogram, and Galaxy views.
The Galaxy is the map, not the raw proof. The proof lives underneath it: frequency lines, timing, noise level,
repeated contacts, and the confidence attached to each event.
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- Node
- One detected sound event: a call, pulse, note, chirp, hum, phrase, or other bounded sound.
⌁
- Position
- Nearby nodes mean the events sound alike or behave alike over time.
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- Size
- Bigger nodes have stronger evidence: louder, longer, clearer, or repeated support.
⟶
- Edges
- Lines show sequence, similarity, repeated motifs, or the same contact appearing again.
What the views mean
≋
Waveform
Amplitude over time, split into useful frequency bands.
▥
Spectrogram
Frequency detail, so high and low sounds separate visually.
✣
Galaxy
The higher-level map built from events, contacts, similarity, and timing.
Why this is real analysis
The app first asks a simple question: where are the actual sounds? It marks the start and end of each event,
measures how strong it is, and checks what frequency range it lives in.
Then it asks whether sounds repeat. If a tone, chirp, call, pulse, or hum keeps showing up, it becomes a
contact track. That makes repeated sources visible instead of letting them disappear into the picture.
The app also watches the background. A quiet call inside a quiet recording is different from the same call
buried in wind, handling noise, traffic, or water movement.
Underwater audio can use the same ideas when the input is a hydrophone, line-in source, or uploaded recording.
A browser cannot magically know direction or distance from one mic, so we call these source tracks, not bearings.
Analysis modules
1EventsFinds where sounds start and stop.
2ContactsGroups repeated sources over time.
3SignaturesShows frequency, rhythm, harmonics, noise, and confidence.
4Noise floorSeparates signal from background clutter.
5RhythmFollows trills, pulses, clicks, and repeated notes.
6DriftShows whether tones rise, fall, or stay stable.
7TextureLabels sounds as tonal, noisy, broad, bright, low, or pulsed.
8MotifsCollects repeated phrases and patterns.
9ReportExports images, contacts, timestamps, and confidence.
Class hints are intentionally cautious: tonal, pulsed, mechanical, wind, or low hum.
They are clues for review, not final labels.
Compare recordings and annotation mode are future workflows. Comparison belongs in the library, and annotation
should let users label contacts or events once the evidence is stable enough to trust.
References
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Robust sound event detection in bioacoustic sensor networks
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Improving Sound Event Detection Metrics: Insights from DCASE 2020
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Clustering and novel class recognition: evaluating bioacoustic deep learning feature extractors
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Global birdsong embeddings enable superior transfer learning for bioacoustic classification
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The SPACE Labelling Tool and Time-Frequency Catalogue workflow
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Pijanowski et al., Soundscape Ecology: The Science of Sound in the Landscape, BioScience, 2011.
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Sharma et al., Contextual and combinatorial structure in sperm whale vocalisations, Nature Communications, 2024.
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Sainburg, Thielk, Gentner, Finding, visualizing, and quantifying latent structure across diverse animal vocal repertoires, PLOS Computational Biology, 2020.
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Hagiwara, AVES: Animal Vocalization Encoder based on Self-Supervision, arXiv:2210.14493.
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Robinson et al., NatureLM-audio: an Audio-Language Foundation Model for Bioacoustics, arXiv:2411.07186.
Library viewer modes
The library page uses a dedicated science-first layout:
Playback Path (single active event + transition node), Repertoire Structure
(neighbor topology and cluster prominence), and Uncertainty Lens (confidence-weighted node emphasis).
The goal is an event graph over time: static when paused, active only at the current sound during playback, and
always traceable back to the underlying recording.