Reverb Time Analyzer vs RT60 Acoustic Panel Test

"Reverb Time Analyzer" is an acoustic analysis tool for iPhone that allows you to measure the reverberation time of a room. Would you like to control sound reverberation in your listening room? Knowing the reverberation time is key to creating a comfortable sound space. For example, you can obtain objective data on various acoustic disturbances, such as high room reverberation, poor intelligibility, excessive flutter echo, and howling. The app can analyze the reverberation time using the interrupted noise method, in which a random test noise signal is generated from the iPhone's speaker and then turned off. Up to six consecutive measurements are possible, enabling reverberation time analysis and spectrogram analysis. Features: - Reverberation time analysis by interrupted noise method: RT30/RT20, RT60 converted from RT30/RT20. - Test source: White noise - Pre-measurement checks and settings (LVL): Measurement of background noise level and adjustment of test signal output level. - Sound pressure level measurement and result display (MSR): Up to 6 consecutive measurements. - Sound recording and playback function - Reverberation time analysis results display (RT): Reverberation decay curve, Reverberation time of each measurement, Sample average reverberation time (Avg) of valid measurement times. - Measurement error detection function. - Octave-band spectrogram (OCT): 1/3, 1/48 octave band. - Delay start time setting: 0 - 60 seconds - Capture function (Snap) Usage: The following steps are used to analyze reverberation time measurements. Step 1 must be performed for each environment. 1) Pre-measurement checks and settings (LVL): Select RT30/RT20 mode. Measure the noise level with "MUTE" and confirm that the appropriate background noise level for reverberation time analysis is less than about 50dB. Then, to ensure the dynamic range of the test sound source, play the output noise signal using "NOISE" and adjust the slider so that the sound pressure level of the observed sound exceeds the red line. If the sound pressure level is insufficient, adjust the iPhone audio volume. Also, if you need to change the RT30/RT20 mode, please start over from the first step. 2) Sound pressure level measurement and result display (MSR): Tap the start button to play a burst of a test sound source and perform sound pressure level measurement and reverberation time analysis. It can be discontinued with the stop button and will automatically stop after 6 consecutive measurements. (Start button is available only when "Avg" is selected.) 3) Reverberation time analysis results display (RT): Displays the reverberation time for each measurement, the average reverberation time (Avg) for valid measurement sessions, and the reverberation decay curve. 4) Octave-band spectrogram (OCT): Displays 1/3 or 1/48 octave band spectrogram analysis results of the observed sound at each measurement session. Notes: - RT60 is obtained by analyzing the time variation of the gain of the observed noise cutoff sound as it decays by 60dB. Since it is quite difficult to actually achieve a dynamic range of 60dB, a reverberation time RT30 with 30dB decay is measured and converted to RT60. Additionally, RT20 is used in cases where RT30's conditions cannot be met (such as when the background noise level is extremely high), but its measurement accuracy is lower than that of RT30. - The reverberation time may not be analyzed correctly if high levels of noise are present during the measurement of background noise or measurement test signals. - The sound level (dB) display is the value of the sound pressure level (Z-characteristics, without frequency weighting correction) received by the iPhone's built-in microphone. Due to its flat response, it generally measures at higher values than a standard sound level meter (dBA). Please visit our iOS app support page for more information on this app.

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.