Privacy Policy

📜 1. Introduction & Core Principle

Welcome to DecibelMaster Pro ("we", "our", or "the App"). We are committed to protecting your privacy and delivering an exceptionally secure, lab-grade acoustic measurement utility.

🔒 100% On-Device Processing Guarantee: DecibelMaster Pro operates entirely on your physical mobile device. We do NOT record, save, store, or transmit your voice, ambient conversations, or audio streams to any external servers, cloud databases, or third parties.

This Privacy Policy explains how our application handles device hardware permissions, acoustic amplitude data, local preferences, and third-party advertising in full compliance with Google Play Developer Policies, the General Data Protection Regulation (GDPR), and the California Consumer Privacy Act (CCPA).

🎙️ 2. Microphone Access & Real-Time DSP Processing

To measure environmental sound pressure levels (SPL) in decibels (dB) and visualize frequency spectrums, DecibelMaster Pro requests runtime access to your device's microphone.

How Microphone Data is Processed:

Mathematical Measurement Only: The microphone stream is passed solely through real-time Digital Signal Processing (DSP) mathematical algorithms (Fast Fourier Transform, A/C/Z frequency weighting, and RMS amplitude detection).
Zero Audio Storage: Audio PCM sample buffers are held temporarily in volatile Random Access Memory (RAM) for fractions of a millisecond and are immediately overwritten. No audio recording files (.wav, .mp3, .aac, etc.) are ever created or saved to your device.
Zero Voice Recognition / Eavesdropping: The algorithm measures raw physical amplitude and frequency distribution only; it does not analyze speech patterns, semantic content, or human voices.
No Network Transmission: Acoustic amplitude calculations remain 100% offline on your device and are never sent over the internet.

🔑 3. Android Permissions & Justifications

Permission	Technical Purpose	Storage & Transmission
RECORD_AUDIO	Captures raw sound pressure amplitudes to calculate real-time decibel (dB) levels and 9-band octave FFT spectrum.	Ephemeral RAM only. Never recorded or transmitted.
FOREGROUND_SERVICE & FOREGROUND_SERVICE_MICROPHONE	Allows occupational noise dosimetry (8H TWA, OSHA/NIOSH dose) and safety alerts to continue reliably when the app is minimized or the screen is locked.	Shows sticky status notification. Controlled entirely by user switch in Settings.
POST_NOTIFICATIONS	Displays the foreground monitoring notification bar and occupational hazardous noise threshold alerts (>85 dBA).	Local system notification service.

🛡️ 4. Background Noise Monitoring & Foreground Service

DecibelMaster Pro includes an optional Background Monitoring feature tailored for occupational safety compliance (OSHA PEL & NIOSH REL):

Explicit User Control: Background monitoring is never initiated silently. It is activated and deactivated solely by the user via the switch in the Settings screen.
Persistent Status Bar Notification: While monitoring in the background, a high-visibility Android notification displays live SPL readings and exposure dose so you are always fully aware that the sensor is active.
Instant Termination: Tapping "Stop" in the notification or disabling the switch instantly terminates the microphone capture session and releases all hardware resources.

💾 5. Local Data Storage & User Exports

All user-generated data remains under your absolute control:

Settings & Preferences: Your preferred theme, language selection, calibration offset (+/- dB), alarm thresholds, and rating preferences are stored strictly in local Android SharedPreferences / Jetpack DataStore on your device.
Measurement History: Saved measurement sessions (min, max, average, peak, TWA, duration, tags, notes) are stored in an encrypted local app-private SQLite database.
Session Exporting: When you choose to export your session data to CSV or JSON, the file is created locally and shared only via the Android System Share Sheet to targets you explicitly select (e.g., Google Drive, Email, Local Files).

📢 6. Third-Party Advertising (Google AdMob)

DecibelMaster Pro is offered as a free application supported by non-intrusive banner and native advertisements provided by Google AdMob.

Google AdMob may collect and process pseudonymous identifiers, such as:

Google Advertising ID (GAID / AAID)
Device model, operating system version, and general network connection type
Coarse non-precise IP-based location for regional ad relevance

You can reset or opt out of personalized advertising at any time by navigating to your Android device settings: Settings > Google > Ads > Delete Advertising ID or Opt out of Ads Personalization.

For more details on Google's privacy practices, please review the Google Privacy & Terms Policy.

👶 7. Children's Privacy (COPPA Compliance)

DecibelMaster Pro does not knowingly collect, solicit, or maintain personal information from children under the age of 13. The application is a general-purpose acoustic utility suitable for all audiences.

🔄 8. Changes to This Privacy Policy

We may update our Privacy Policy from time to time to reflect technological improvements, operating system changes, or statutory requirements. Any updates will be posted directly within this page with a revised "Last Updated" timestamp.