AudioSpectrumWaterfall

Audio Spectrum analyzing app for audio researchers, musician and geeks, now ON SALE FOR FREE!

A real-time audio analyzer for iPhone and iPad. Five panes cover spectrum, waterfall, oscilloscope, peak list, and note/chord detection — pick any combination and arrange them in a custom layout.

PANES

Spectrum — live magnitude spectrum in three drawing styles (Trace, Line, Bars), peak-hold trace, peak markers, and a drag-anywhere cursor showing frequency, level, and nearest note.

Waterfall — scrolling spectrogram with six color maps and adjustable scroll speed.

Time Domain — oscilloscope with rising-edge trigger, automatic vertical gain, and min/max envelope drawing.

Notes & Chords — detected fundamentals with cents-accurate tuning meters and chord name readout.

Peak List — top N interpolated spectral peaks with frequency, level, nearest note, and cents offset.

Panes stack vertically and split into two columns on wide, short windows (iPad landscape, phone landscape). Five built-in layout presets are included: Spectrum + Waterfall, Scope + Spectrum, Musician, Analyser, and Everything.

ANALYSIS CONTROLS

FFT size from 256 to 32768 points. Window functions: rectangular, Bartlett, Hann, Hamming, Blackman, Blackman-Harris, flat top, Kaiser. Exponential averaging and adjustable refresh rate. Live readout of frequency resolution (Hz/bin) and window length (ms). Amplitude scale: linear or dBFS, with adjustable level range. Frequency scale: linear or logarithmic, with adjustable frequency range. Spectrum style: Trace (every FFT bin plotted individually, no resampling) or Line/Bars (per-pixel peak or average detector).

NOTE AND CHORD DETECTION

Harmonic-comb analysis with iterative spectral subtraction identifies fundamental frequencies and matches them against 19 chord templates across all 12 roots, including slash-chord naming. A spectral-flatness gate skips pitch detection on broadband, non-tonal input (percussion, breath, room noise), with an adjustable sensitivity threshold. The spectrum, waterfall, and peak list always display the raw, unmodified spectrum — harmonic reduction is applied only to the note and chord readout.

AUDIO INPUT

Works with any input source exposed by the system: built-in microphone (including individual top/bottom/front/back elements where supported), wired headsets, USB audio interfaces, and Bluetooth headsets. Sample rate can follow the hardware or be fixed at 8, 16, 22.05, 32, 44.1, 48, or 96 kHz. Automatically handles route changes (headphones unplugged, Bluetooth reconnects) and interruptions (phone calls).

SIGNAL GENERATOR

Built-in generator produces sine, sawtooth, square, triangle, white noise, pink noise, a logarithmic sweep, or a major triad — useful for testing scale settings and window behavior without external audio. Nothing is routed to the speaker.

DISPLAY CONTROLS

Freeze the live display at any point, and start or stop capture manually. A status bar shows RMS/peak level with a clipping indicator, the current audio route, sample rate, FFT size, Hz/bin resolution, and window length.

PRIVACY

Audio is analyzed in real time on-device only. It is never recorded or transmitted.

REQUIREMENTS

iPhone and iPad, iOS 17.0 or later. Microphone access required for live audio capture. English only.