RT60 Acoustic Panel Test

RT60 Acoustic Panel Test turns your iPhone into a survey-grade reverberation time analyzer based on ISO 3382-2. One clap is all it takes. The app captures the impulse response through your device microphone, filters it into six standard octave bands (125 Hz, 250 Hz, 500 Hz, 1 kHz, 2 kHz, 4 kHz), builds Schroeder decay curves, and extracts T20 and T30 regression values - exactly the method described in the ISO 3382 international standard for room acoustics. WHAT YOU GET - RT60 per octave band - see which frequencies decay too fast or ring too long. - T20 and T30 values - toggle between the two regression windows to compare linearity and dynamic range. - Broadband average (125 Hz - 4 kHz) and speech-band average (250 Hz - 2 kHz) calculated automatically. - Pass / Warning / Fail rating for every band, evaluated against ISO-recommended targets for your chosen room type. - R-squared quality flag - bands that fall below the ISO 3382 minimum coefficient of determination (R-sq below 0.90) are marked "Unreliable" so you know when to remeasure. ROOM TYPES WITH ISO TARGETS Choose from seven room presets, each with ISO-recommended RT60 target ranges: - Home Office / Podcast Studio (0.3 - 0.5 s) - Open Office (0.4 - 0.6 s) - Classroom / Meeting Room (0.4 - 0.7 s) - Conference Room (0.5 - 0.8 s) - Recording Studio (0.2 - 0.4 s) - Home Theatre (0.3 - 0.5 s) - Concert Hall (1.5 - 2.2 s) SABINE CROSS-CHECK Enter room dimensions and surface materials (floor, ceiling, walls) to compute a theoretical RT60 via the Sabine-Eyring equation. The Sabine estimate plots alongside your measured values so you can see how theory compares to reality - useful for diagnosing unexpected results or planning acoustic treatment. PROFESSIONAL PDF REPORT Generate a full PDF measurement report that includes: - Measurement conditions (date, background noise, temperature, humidity) - Spider chart and frequency-response line chart with T20, T30, and Sabine overlays - Per-band RT60 table with pass/fail status - Broadband and speech-band averages - ISO-compliant disclaimer noting survey-tier methodology Share or save the report directly from the app. ENVIRONMENTAL CONDITIONS Temperature and humidity are logged automatically via a weather API using your GPS location, or you can enter indoor readings manually. Background noise is measured before each test so the app can set the impulse detection threshold correctly. MEASUREMENT HISTORY The last five measurements are saved with their full PDF reports. Re-open any previous session to review graphs and data or reshare the report. HOW IT WORKS 1. Select your room type. 2. Place your phone on a stable surface near the centre of the room. 3. Tap Start, step back, and clap once. 4. Review results in seconds. The DSP pipeline runs in an isolate so the UI stays fluid. Octave-band filtering uses second-order IIR bandpass filters; onset detection uses a rolling energy window with adaptive thresholds; decay analysis applies Schroeder backward integration followed by linear least-squares regression over the T20 (-5 to -25 dB) and T30 (-5 to -35 dB) evaluation ranges - all per ISO 3382-2. No calibrated equipment is required. Results are survey-tier (indicative), not engineering-grade. For traceable measurements, use calibrated instrumentation operated by a qualified acoustician. Supports metric and imperial units.