Decibel Meter: Sound Level

🔊 DecibelMaster Pro — Precision Sound Level Meter (SLM), Occupational Noise Dosimeter & Real-Time 9-Band FFT Octave Frequency Spectrum Analyzer!

Engineered to meet rigorous acoustic measurement standards (IEC 61672-1 Type 2 compliance), DecibelMaster Pro transforms your Android smartphone into a professional, lab-grade sound pressure level (SPL) meter. Whether assessing workplace noise safety (OSHA / NIOSH compliance), tuning studio acoustics, investigating neighborhood noise, or monitoring hearing health, DecibelMaster Pro delivers unparalleled measurement precision, beautiful visual telemetry, and 100% on-device privacy.

🌟 CORE FEATURES & CAPABILITIES:

1. 🎙️ Laboratory-Grade Sound Level Meter (SPL)
• Real-time digital sound pressure measurement with ultra-responsive analog dial and high-visibility digital readout.
• Frequency Weighting Filters:
- A-Weighting (dBA): Replicates human ear response for everyday environmental & occupational noise.
- C-Weighting (dBC): Captures low-frequency bass, engine rumble, subwoofers, and machinery noise.
- Z-Weighting (dBZ): Flat acoustic response across the audible spectrum.
• Time Weighting Dynamics: Fast (125ms) for rapid transients and Slow (1000ms) for stable time-averaged levels.
• Complete statistical matrix: Instantaneous dB, MIN, Time-Average (AVG / Leq), MAX, and Absolute PEAK.

2. 📊 Real-Time 9-Band 1/1 Octave FFT Spectrum Analyzer
• Radix-2 Cooley-Tukey Fast Fourier Transform (FFT) algorithm with Hann windowing.
• Visualizes acoustic energy across 9 standard IEC octave frequency bands:
63 Hz, 125 Hz, 250 Hz, 500 Hz, 1 kHz, 2 kHz, 4 kHz, 8 kHz, and 16 kHz.
• 3 interactive visualizer modes: Real-Time Oscilloscope Waveform, Chrono-Trend History Line, and 9-Band Animated Equalizer.

3. ⏳ Occupational Noise Dosimeter & 8-Hour TWA
• Dual Standards Support:
- OSHA PEL: 90 dBA Criterion, 85 dBA Threshold, 5 dB Exchange Rate.
- NIOSH REL: 85 dBA Criterion, 80 dBA Threshold, 3 dB Exchange Rate.
• Computes Cumulative Shift Dose (%), Remaining Safe Permissible Hours, and 8-Hour Time-Weighted Average (8H TWA).
• Extrapolates Projected 8-Hour Daily Dose in real-time.

4. 🛡️ Background Monitoring Foreground Service
• Continuous acoustic monitoring with screen locked or app minimized.
• Low-overhead persistent status bar notification displaying live decibel levels and hazardous noise warnings.
• Instant notification alerts when sound levels exceed danger thresholds (e.g. 85 dBA).

5. 📁 Session Recording, History & CSV/JSON Export
• Save full measurement runs with titles, location tags, and custom notes.
• Review past sessions with interactive telemetry cards and historical trend graphs.
• Export session data seamlessly to CSV and JSON for safety audits or noise complaints.

6. 🎯 Manual Acoustic Offset Calibration
• Fine-tune microphone sensitivity (+/- 20.0 dB in 0.1 dB increments) against calibrated reference sound sources.

7. 🌓 3 Curated Themes & Multi-Language Engine
• Dark Studio, OLED Stealth Pitch Black, and Acoustica Clean Light.
• Fully localized across global languages with instant dynamic switching.

🔒 100% PRIVATE — ZERO AUDIO RECORDED:
DecibelMaster Pro computes sound pressure purely in ephemeral RAM. No audio or voice recordings are ever recorded, saved to storage, or transmitted over any network.

⚖️ LEGAL DISCLAIMER:
Intended for personal awareness, education, and reference monitoring. Built-in smartphone microphones cannot substitute certified Class 1 / Class 2 laboratory instruments.