Privacy Policy

1. Zero Audio Recording & Zero Data Collection

When you grant microphone permission on Free Online Decibel Meter, raw sound pressure fluctuations are captured in volatile browser memory solely to compute instantaneous decibel sound pressure levels (dB SPL).

• No Audio Files: No audio recordings, WAV/MP3 files, or voice samples are ever saved to your device disk or cloud servers.
• No Audio Streaming: The audio data stream never leaves your local computer, tablet, or phone.
• No Speech Recognition: We do not transcribe speech, process conversational semantics, or generate voiceprints.
• No Biometric Identification: We never extract biometric acoustic signatures.

2. How the Web Audio API Operates

Our web application uses the W3C standard Web Audio API (via navigator.mediaDevices.getUserMedia). When you click "Start Measuring":

• Your browser creates an in-memory AudioContext and an AnalyserNode.
• The browser reads raw numeric amplitude buffers (Float32Array) at 60 FPS to calculate the mathematical Root Mean Square (RMS) energy: dB = 20 * log10(RMS) + CalibrationOffset.
• When you click "Stop Measuring", close the browser tab, or navigate away, the audio stream tracks are immediately stopped via stream.getTracks().forEach(track => track.stop()) and the audio context is closed, releasing your microphone instantly.

3. Browser Local Storage Usage

To provide you with a customized experience across visits without requiring an account or login, we store a minimal set of user preferences in your browser's local storage (localStorage):

• real_decibel_meter_theme: Remembers your UI theme preference (Light or Dark mode).
• real_decibel_meter_style: Remembers your selected meter visual interface (Classic Gauge, Digital LED, Waveform FFT, Minimal Clean, or Futuristic HUD).
• real_decibel_meter_lang: Remembers your chosen display language.

This preference data is stored locally in your own browser, is never synchronized to an external database, and can be cleared at any time by clearing your browser site data.

4. Cookies & Third-Party Trackers

Free Online Decibel Meter is built to be clean and privacy-respecting. We do not use intrusive cross-site tracking cookies, behavioral tracking pixels, or third-party fingerprinting scripts. We do not sell, rent, or monetize your personal information.

5. How to Revoke Microphone Permissions

You have full control over your device microphone at all times. If you wish to revoke microphone access, you can do so in a few clicks depending on your browser:

• Google Chrome & Microsoft Edge: Click the "Tune / Lock" icon next to the URL in your address bar → toggle Microphone to Off or "Ask (default)".
• Apple Safari (iOS / iPhone / iPad): Open Settings → Safari → Microphone → choose "Ask" or "Deny".
• Apple Safari (macOS): Open Safari Settings → Websites → Microphone → find freeonlinedecibelmeter.com → select "Deny".
• Mozilla Firefox: Click the permissions icon on the left side of the address bar → click the "X" next to Allowed Temporarily / Blocked.

6. Children's Privacy (COPPA & GDPR Compliance)

Our decibel measurement tool is completely safe for audiences of all ages, including students and children conducting science classroom acoustic experiments. Because we do not collect personal identifying information (PII) or audio recordings, our service fully complies with the Children’s Online Privacy Protection Act (COPPA) and General Data Protection Regulation (GDPR).

7. Changes to This Privacy Policy

We may periodically update this Privacy Policy to reflect enhancements to our web application or changes in legal regulations. Any updates will be posted directly to this page with an updated modification date.

8. Contact & Security Inquiries

If you have questions regarding this Privacy Policy or our local client-side Web Audio architecture, please reach out to us through our Contact Page or review our Frequently Asked Questions. Contact Page or review our Frequently Asked Questions.