Spectrum Eye RTA

Live RTA for iPhone and iPad. Spectrum Eye shows the frequency content of what your mic or interface is hearing - smoothly, at high FFT sizes, without freezing the UI. Version 2 is a full rebuild: Metal plot, bars / line / spectrogram, calibrated SPL, and mic correction on the live spectrum. For music professionals, audio engineers, sound technicians, installers, car audio, and audio students. Equally at home as a quick check or a plot you leave running. WHAT YOU CAN DO • Monitor sound quality at concerts and rehearsals • Ring out feedback in stage monitors • Find resonances in rooms, boxes, instruments and cars • Check spectral balance of playback in the studio • Practice frequency-aware hearing • Measure SPL with A / C / Z weighting and Fast / Slow / Leq PLOT • Bars, line, and spectrogram - the configuration button is in the top right corner • Fractional-octave resolution from 1/1 through 1/96 • Line smoothing follows the same octave map • Peak hold with a slow release, optional fill under the line • Find Peak (FP) tracks the loudest band in the visible range • Classic or Overlay layout treats plot area vs scales differently; Overlay is the default • Pan, pinch-zoom, and a live cursor in Hz and dB • Frequency visible range presets (Full 8 Hz–22 kHz, Audio, Lows, Mids, Highs) • Magnitude-range presets • Spectrogram duration, Jet / Viridis / Inferno / Grayscale color palette • Light, Dark, or System appearance, plus a custom plot color • Spectrum update rate: 60 fps Smooth, 30 fps Efficient, or Auto (drops under heat or Low Power Mode) SPL • IEC-style meter: Fast, Slow, and Leq • A, C, and Z (flat) frequency weighting • Per-route SPL offset so you can calibrate against a reference • Yellow / red SPL alarm thresholds per weighting, with UI tinting • Clip indicator and a 30–140 dB level meter bar • iPhone: Large panel in portrait device orientation; in landscape orientation, compact readout in the top bar • iPad: switchable large and compact SPL mode INPUT AND CALIBRATION • Built-in mics (including iPad position / directivity where the device offers them) • External microphones and class-compliant audio interfaces • iOS measurement mode to bypass built-in HPF, EQ, and AGC (recommended) • Import mic calibration files (.cal, .txt, .csv); optional phase column is ignored • Per-route calibration curve and IEC weighting on the live spectrum • Pink noise generator, including with the screen off (Lock Screen / Now Playing) ANALYSIS • FFT sizes 4K / 8K / 16K / 32K (default 16K) • Fall-rate presets: 50 ms, 100 ms, 250 ms, 500 ms, 1 s, 5 s per 6 dB • Nominal capture sample rate - 48 kHz, display ranges from 8 Hz to 22 kHz Audio is processed on the device. Spectrum Eye does not record, store, or upload your audio. Suggestions welcome - the app is in active development.