FNam FFT Spectrogram Analyzer

FormulaNam

About this app

■ FNam FFT Spectrogram Analyzer
Engineers need tools that are ready to use — anytime, anywhere.
FNam FFT Spectrogram Analyzer turns your smartphone into a
professional audio analysis tool. Unlike typical sound meter apps,
it delivers advanced features like Dual File Comparison and CSV
Export for precise post-analysis

* completely free, no ads (core features).
Real-time FFT & Spectrogram / All processing runs on-device /
No audio data uploaded externally.

■ NEW FEATURES
1. Sound Event Logger
- A feature that continuously monitors audio, automatically logging data and saving a WAV file whenever the sound level exceeds a predefined threshold.
- Includes a screensaver to minimize screen burn-in.
- The log files are generated using the FNam JSON schema to support AI and data analysis.

2. Frequency Response Preview (requires FNam Frequency Noise Generator)
- WiFi TCP-based acoustic frequency response measurement.
- Requires FNam Frequency Noise Generator — available via trial ad or premium subscription in the Noise Generator app.

■ Turn your smartphone into a professional audio analysis tool.

[Video Guide - See it in action]
https://youtu.be/72SYLTG0l_8

FNam FFT Spectrogram Analyzer is a precision tool designed for sound engineers, researchers, students, and audio enthusiasts who need accurate frequency analysis and data logging.

■ KEY FEATURES

1. Real-time Audio Analysis
• High-precision FFT (Fast Fourier Transform) Graph.
• Time Domain Waveform (Oscilloscope) view.
• Fluid Spectrogram for visualizing frequency changes over time.

2. Dual File Comparison (Exclusive Feature)
• Simultaneous loading of two WAV files for comparative analysis.
• Spectrum Overlay: Visually compare differences using color-coded traces (Blue vs. Magenta).
• Instant Calculation: Provides Arithmetic Mean and Mean Difference between signals.

3. Data Logging & Export
• Flexible Sampling Rates: Supports various rates (4000Hz, 8000Hz, 16000Hz, 22050Hz, 44100Hz).
• High-quality Recording: Audio is recorded and saved as WAV files, strictly matching the selected sampling rate.
• Raw Data Export: Exports raw PCM data to CSV format. The exported data maintains the exact sampling rate and duration, making it optimized for post-processing in Excel, MATLAB, or Python.
• File Management: Files are stored in the 'Download\FNamDoc' directory.
- WAV naming format: Date_Time_SampleRate_Channel.wav
ex) 20260219_164715_44100Hz_Mono.wav

- CSV naming format: Selected WAV file name_SampleRate_Duration(s).csv
ex) 20260219_164715_44100Hz_Mono_44100_5.2s.csv

4. Professional Configuration
• Window Functions: Selectable Rectangular, Hann, Hamming, and Blackman windows.
• Frequency Weighting: Supports A, B, C, and Z (Linear) standard weighting filters.
• Axis Control: Supports both Auto-scaling and Manual range settings (Hz / dB) for precise graph inspection.
• Calibration: dB SPL offset tuning for FFT and Time Domain measurements to compensate for differences from professional equipment.
• Max Peak Hold: Displays and holds the maximum amplitude values across the frequency spectrum.
• Frequency Response Preview: WiFi TCP-based acoustic frequency response measurement (requires FNam Frequency Noise Generator).

■ TECHNICAL SPECIFICATIONS
• Signal Processing: Anti-aliasing filters are automatically applied during downsampling to ensure measurement accuracy.
• Sampling Rate: Supports standard rates up to 44.1kHz (device dependent).
• Standards: Implements IEC 61672 formulas for accurate weighting calculations.

⚠️ Note: While this app uses IEC 61672 standard formulas, measurement discrepancies compared to professional equipment may occur due to the hardware frequency response limitations of the built-in smartphone microphone. For critical measurements, the use of a calibrated external microphone is recommended.

What’s new

- Fixed a layout issue where the 'Got it!' button was pushed off-screen on large display devices
- Fixed minor bugs
- Added Frequency Response Preview (requires FNam Frequency Noise Generator)
- Added bilinear interpolation smoothing to spectrogram