RT60 Acoustic Panel Test vs Evir

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.

Evir converts, compresses and edits your videos, audio, images and PDFs — fast, private and entirely on your device. No uploads, no waiting for a server, works offline. 35 tools in one app. VIDEO • Convert between MP4, MOV, MKV, WebM, AVI and more • Compress to a fraction of the size — or straight to a target like WhatsApp, Email, Discord or Telegram • Extract audio as MP3, M4A, WAV, FLAC and more • Trim, crop, rotate, change aspect ratio, change speed • Merge clips into one video • Reverse a video or make a boomerang • Watermark videos and photos with a logo or text, in batches • Subtitles: transcribe speech into SRT, VTT or TXT and burn captions in • Eraser: blur or cover a region • Video to GIF SOCIAL STUDIO Turn photos and videos into stories, reels and posts: templates, music and AI voice, animated text, on-device captions, stickers, looks and safe-zone guides for every platform. AUDIO • Convert between MP3, M4A, WAV, FLAC, OGG and more • Trim, merge, split and change speed • Enhance: noise reduction and loudness levelling • Text to Speech: read any text aloud into an audio file • Make a ringtone IMAGE • Convert between HEIC, JPG, PNG, WebP and more • Crop and optimize images • Cut Out: remove a photo's background • Extract Text: pull text from images and PDFs into a searchable PDF • Turn images into a PDF PDF • Scan documents with the camera • Compress, merge, split and password-protect PDFs • Export PDF pages as images PRIVATE BY DESIGN Everything runs locally on your iPhone and iPad, including speech recognition, background removal and text recognition. Your files never leave your device — nothing is uploaded or stored on a server. No account, no ads. SIMPLE AND FAST Pick a file, choose a format or size, and go. Batch-convert several clips at once. Your finished files are collected in one library, ready to preview, save or share. Ask Apple Intelligence which tool to use and it takes you there. Whether you're shrinking a video to send it in a chat, pulling the audio out of a concert clip, captioning a reel or turning a stack of photos into a PDF, Evir gets it done in seconds.