Hysteric Oscillator 波動

An oscillator experiment app that shows the waveform in real time while it plays.

Generate sine, square, pulse, sawtooth, and noise from 2 Hz to 20 kHz, and control the filter (low-pass / high-pass) and AM / FM modulation from your device. Export what you made as a video or an audio file. Useful for quick speaker and amplifier checks, DIY audio circuit tests, and learning synthesizer basics.

Features
- Six waveshapes: sine, square, pulse, sawtooth, harmonics, and noise (White, Pink, or Brown)
- Real-time waveform display with L / R in separate colors; tap to switch to a mono trace
- Spectrum analyzer: see the frequency content in real time, with guide lines on each harmonic so you can read how much harmonic content the sound has
- "Harm" waveshape built from added harmonics: pick which harmonic is loudest with a slider, then set the character with Pure / Full / Odd / Even, and check the result in the spectrum
- Frequency from 2 Hz to 20 kHz, with exact numeric entry
- Filter: off / low-pass / high-pass, with resonance (Q) and slope (-12 to -48 dB/oct)
- AM modulation with five modulator shapes; pulse lets you set the beep length in milliseconds
- FM modulation with five modulator shapes: vibrato, trill, siren and hiccup-style pitch movement
- Stereo balance control
- 39 built-in presets (bandwidth-check sine tones, filter and pulse driven effects)
- Export a vertical video (MP4) of the moving waveform for social media (free)
- Export audio files (WAV / M4A) with the Full Version
- Two channels for interference and beating (Full Version)
- Save and share your own presets (Full Version; the same file format as the iOS app, so presets travel between devices)

Great for
- Quick checks of speakers, earphones, and amplifiers
- Testing DIY effects pedals and audio circuits
- Learning waveforms, filters, and modulation
- Classroom and workshop demonstrations
- Playing with drones, beats, and modulated tones

Free and Full Version
The oscillator, waveform display, filter, modulation, numeric entry, and video export are free. Two-channel operation, preset saving and file sharing, audio file export, and alternate app icons are available through a one-time in-app purchase.

Note
This app is intended for experiments and quick checks, not precision measurement. Start at a low volume, and take care when connecting earphones, headphones, or external speakers.