SOUNDMARK · FIELD RECORDER
VIBRATIONS COLLECTED FROM THE WORLD
A nocturnal field-recording notebook. Record whatever you can hear right now, trim the ends off, give it a title and a place, attach a photo if it helps — then let your iPhone take it apart: waveform, spectrum, spectrogram, dominant frequency, loudness, spectral centroid, zero-crossing rate. Every recording takes its colour from its own dominant frequency.
iOS 17 or later · iPhone · every calculation runs on the device, offline.
24h convenience store
0:35 / 1:32
Open the recorder and tap. 48 kHz sampling, with the live waveform and dominant frequency moving with whatever is in front of you. Pick the back, front or bottom microphone — for ambience, the one facing the world is usually the right one.
Drag the two handles until only the part worth keeping is left. Trimming writes a new file and re-runs the analysis, so the colour follows the new dominant frequency.
Add a title, a place and a description. The place is a line of text you type — the app never reads your location. Attach a few photos or a video if the moment needs them.
Every recording is analysed in full the moment you save it — FFT and short-time Fourier transform through Accelerate, on the device. No queue, no upload; it finishes just the same in airplane mode.
During playback the spectrum tracks the playhead — it reads the real STFT column under it, not a decorative shimmer.
The dominant frequency, 60 Hz to 4 kHz, is taken on a log scale and mapped onto hues from 25° (amber) to 285° (violet). The low hum of a convenience-store freezer runs warm; the fine hiss of a mountain stream runs cold. The colour isn't decoration — it's a reading.
Home · balcony
West hills · behind the ridge
24h convenience store
No accounts, no servers, no analytics, no third-party SDKs. Recordings, attachments and the index are written into the app's own Documents directory. Delete a recording and its audio and attachments go with it; delete the app and everything is gone.
Open it and record. Nothing to sign up for, sign in to or subscribe to — we don't know who you are.
There is not a single network request in the code. The app is complete in airplane mode.
“Place” is a line of text you type yourself. The app never reads your location.