Morlet
Spectrum & Wavelets for iPhone and iPad
Morlet shows the sound around you as a live, scrolling picture of frequency over time. It has two views: a Fourier spectrum and a wavelet scalogram. You can tap anywhere on the graph to read the frequency, note and level, see the loudest pitch like a tuner, and record sessions to export as audio and data. Morlet is free, with no ads, accounts or in-app purchases.
Getting started
Start listening
Tap the microphone button and allow microphone access when asked. The graph begins scrolling from the right, with low frequencies at the bottom and high frequencies at the top.
Choose a view
Spectrum is steady and easy to compare across the range. Wavelet gives low sounds precise pitch and high sounds precise timing.
Pick settings for what you are hearing
Open the sliders button and tap Which settings should I use? for one-tap setups for music, speech, drums, hum and birdsong, plus an explanation of every setting.
Questions
Can I analyze a song or voice memo?
Yes. Tap the list button, then Open Audio File, and choose any audio file from Files. You can also use the share button in Voice Memos or another app and pick Morlet. The file plays with the graph scrolling in sync, and you can drag the slider to jump to any point. Your own recordings have a play button in the same list.
How do I save or share the graph?
Tap the picture button in the corner of the graph. Morlet makes an image of the current view with its labels and settings, ready to save or send.
How do I read a specific point on the graph?
Tap or drag on the graph. A crosshair shows the frequency, nearest note, level and how long ago that moment was. Use the pause button on the graph to freeze the picture while you look. The microphone and any recording keep running.
The pitch readout or pitch line jumps around.
Pitch is detected from about 40 Hz to 4 kHz and needs a single clear note, so chords, noise and very breathy sounds can confuse it. Sing or play one note at a time close to the microphone. You can turn the pitch line off in settings under Curve and pitch.
What is the tone generator for?
The tuning fork button plays a sine, triangle, square or sawtooth tone, or sweeps from 20 Hz to 20 kHz. Start listening first to watch the tone and its harmonics on the graph, or to see how your speaker and microphone respond across the range. Keep the volume low with headphones.
Can I change the colors?
Yes. In settings, under Appearance, choose Light, Dark or Match System, and pick any accent color. Under Display, choose the graph colors: Ink, Sepia, Inferno, Grayscale, the original Neon, or Custom with colors you pick yourself.
The graph is too dark or too bright.
Adjust Brightness and Contrast in the Display section of settings. They change only the picture, not the analysis or exports.
Where are my recordings?
Tap the list button at the top of the screen. You can share or delete each recording there. Recordings are stored only on your device and are removed if you delete the app.
What do the exported files contain?
audio.wav: the recording as uncompressed audio.analysis.csv: one row per analysis frame, with a time column, spectrum columns in dBFS, and wavelet columns in dB.metadata.json: the settings used, so the data can be interpreted later.
Morlet says microphone access is disabled.
Open the Settings app, scroll to Morlet, and turn on Microphone.
Why do the very top rows look empty?
Many sounds have little energy at the highest frequencies, and some microphones and headsets cut off early. Lower the Highest frequency in settings to spend the rows on the range you care about.
Contact
Found a bug or have a suggestion? Open an issue on GitHub. It helps to include your device model, iOS version and the settings you were using.