Soundmark: Sound Collection
Field recorder & spectrogram
Only for iPhone
$0.99 · Designed for iPhone. Not verified for macOS.
iPhone
Record what you can hear right now. Soundmark takes it apart on the device — waveform, spectrum, spectrogram, dominant frequency — and gives it a colour of its own.
A nocturnal field-recording notebook.
Record whatever you can hear right now — rain on a balcony awning, the wind a train pushes out of a tunnel, a convenience-store freezer at two in the morning. Trim the ends off, give it a title and a place, attach a photo if the moment needs one. Then let your iPhone take it apart.
ANALYSED ON THE DEVICE
Every recording is analysed in full the moment you save it: FFT and short-time Fourier transform, on the phone. You get the waveform, the spectrum, a spectrogram, and a Fourier-series view that draws the five strongest components as sine curves — alongside dominant frequency, loudness in RMS dB, spectral centroid, zero-crossing rate and sample rate. No queue, no upload; it finishes just the same in airplane mode.
THREE STEPS INTO THE LIBRARY
• Record — 48 kHz, with the live waveform and the dominant frequency moving with whatever is in front of you. Choose the back, front or bottom microphone; for ambience, the one facing the world is usually the right one.
• Trim — drag the two handles until only the part worth keeping is left. Trimming writes a new file and re-runs the analysis.
• Note — add a title, a place and a description, and attach photos or a video if the moment needs them.
EVERY SOUND GETS ITS OWN COLOUR
The dominant frequency, 60 Hz to 4 kHz, is taken on a log scale and mapped onto hues from amber to violet. The low hum of a freezer runs warm; the fine hiss of a mountain stream runs cold. The colour isn't decoration — it's a reading, and it follows the audio when you re-trim it.
WHILE IT PLAYS
Scrub the waveform with your finger and the spectrum follows the playhead, reading the real STFT column underneath it rather than a decorative shimmer.
NOTHING LEAVES THE PHONE
No accounts, no servers, no analytics, no third-party SDKs, and not a single network request anywhere in the code. Recordings, attachments and the index are written into the app's own Documents directory and synced nowhere. The place is a line of text you type — the app never reads your location. Photos and video arrive through the iOS picker, so Soundmark never gets access to your photo library. Delete a recording and its audio and attachments go with it; delete the app and everything is gone.
FREE
No in-app purchases, no subscription, no ads.
iOS 17 or later. iPhone. Dark by design — it was made for the hours when the world is quiet enough to hear.
Ratings & Reviews
- This app hasn’t received enough ratings or reviews to display an overview.
The developer, 鹏帆 张, indicated that the app’s privacy practices may include handling of data as described below. For more information, see the developer’s privacy policy .
Data Not Collected
The developer does not collect any data from this app.
Accessibility
The developer has not yet indicated which accessibility features this app supports. Learn More
Information
- Seller
- 鹏帆 张
- Size
- 26 MB
- Category
- Lifestyle
- Compatibility
Requires iOS 17.0 or later.
- iPhone
Requires iOS 17.0 or later. - Mac
Requires macOS 14.0 or later and a Mac with Apple M1 chip or later. - Apple Vision
Requires visionOS 1.0 or later.
- iPhone
- Languages
English and 4 more
- English, French, Japanese, Simplified Chinese, Spanish
- Age Rating
4+
- 4+
- Copyright
- © 2026 OZLab
