A professional audio toolkit for live sound engineers. Audio Spectrum Pro is a complete measurement suite on your iPhone: spectrum analyzer, chromatic tuner, oscilloscope, loudness meter, test-signal generator, and RT60 reverberation time measurement. Everything in one app, with a dark interface built for the stage and the concert hall. SPECTRUM ANALYZER Real-time spectrum from 50 Hz to 16 kHz on a logarithmic scale. Automatic peak detection highlights problem frequencies instantly. The "EQ Suggestions" panel tells you which band to cut and by how many decibels - before feedback ever happens. CHROMATIC TUNER High-precision pitch detection accurate to hundredths of a cent. Supports guitar, bass, violin, viola, cello, ukulele, mandolin, banjo, and a chromatic mode. Adjustable A4 reference, capo support, and a noise gate to reject bleed from the PA. OSCILLOSCOPE Real-time waveform display for signal-integrity checks, phase inspection, and clipping detection. The first thing you reach for when something sounds wrong. LOUDNESS METER Simultaneous RMS and true-peak readout with a scrolling history graph (120 frames). Watch your average level and catch peak spikes before they slam your limiters. TEST-SIGNAL GENERATOR Pink noise, white noise, a logarithmic sine sweep (20 Hz to 20 kHz), or a fixed tone from 50 Hz to 8 kHz - all played through the speaker while the mic keeps analyzing. Tune PA systems, ring out monitor wedges, and find room resonances without a separate signal generator. RT60 REVERBERATION ANALYSIS Tap Start, make an impulse (a clap, a click, or a sine sweep) - the app records the decay, computes T20, and extrapolates RT60. Size up a room's acoustics in seconds and know whether they're working for you or against you. BUILT FOR THE FIELD - Mic gain control with the volume buttons - one hand, while the other stays on the console - Fully dark interface - readable under stage lighting, easy on your night vision - Landscape orientation - lay it on the meter bridge or a side table - Three interface languages: English, Russian, Ukrainian Microphone access is required. A speaker or headphones are needed to play test signals.