Transform Your Phone into a Sound Level Meter and Spectrum Analyzer


This application integrates the functionalities of a Sound Level Meter (SLM) and a Real Time Spectrum Analyzer (RTA) directly onto your smartphone. It measures the Sound Pressure Level (SPL) in decibels (dB) using either the internal or external microphone.

Ideal for Acoustic Measurements



  • SLM: Analyze traffic or ambient noise (TNI, dBA/dBB/dBC, Leq)

  • RTA: Assess audio equipment frequency response (spectrum, octaves, peaks, RMS)

Enhanced Features of the Application


This app offers numerous advanced features compared to the basic edition (ad-free).

SLM Main Features



  • Measurements in SPL

  • Three measuring modes: Dynamic, Average, Cumulative

  • Three weighting filter curves: dBA, dBB, dBC according to DIN-IEC 651

  • Fast and easy calibration page

  • Sound level versus time chart

  • Current dB value, average (Leq), minimum and maximum display

  • Leq (wideband, RMS of the observation period)

  • Audio threshold trigger

  • Sound level distribution chart

  • Accumulated sound level chart

  • Display of current value, Leq, L90, L50, and L10 values

  • TNI (Traffic Noise Index) display

  • Exporting of measurements, chart data (CSV), and screenshots (PNG)

  • Tested with Samsung Galaxy

  • Sharing of text values and screen BMP

RTA Main Features



  • Measurements in SPL

  • Five spectrum measuring modes: Dynamic, Average, Peak, Avg/Exp Smoothing

  • Sound level versus linear frequency chart

  • Sound level versus logarithmic frequency chart (HzLog)

  • 1/1 Octave Bands chart

  • 1/3 Octave Bands chart

  • Microphone Equalizer (Internal or External) in 1/1 Octave bands

  • Calibration in 1/1 Octave bands

  • Two spectrum views: Panel & Chart, Landscape Chart

  • Tap or swipe to select the proper frequency step

  • Long press to zoom

  • Display of four values versus selected frequency component (current, Leq, max, min)

  • Leq (Octave, RMS of the observation period)

  • Leq (selected frequency, RMS of the observation period)

  • 20Hz/22kHz band, 44100 Hz sampling rate

  • Adjustable FFT size (up to 8192, about 5 Hz accuracy), adjustable FPS (up to 20)

  • Exporting of measures/chart data (CSV) and screenshots (PNG)

Data Collection Tips


The application relies on the mobile microphone signal. To achieve the best results, consider the following:



  1. Easy Calibration (only the first time): Some mobiles are automatically calibrated during the first installation phase. For details, see the calibration section of the user manual.

  2. Keep your fingers away from the mobile microphone.

  3. Silence your phone to avoid any ring tones, vibrations, and other sounds.

  4. Orient the phone microphone toward the noise source while maintaining the correct distance.

  5. Click on the function buttons to initiate measurements.

Troubleshooting



  1. Wrong SPL/RTA calibration: Refer to the calibration section.

  2. No signals detected below 20dB or over 100dB: Most smartphone microphones do not function below 20 dB or above 100 dB.

  3. Signal attenuation near band limits: The mobile mic may attenuate frequencies < 100 Hz and > 15000 Hz.

Need Help?


For any information or troubleshooting, please refer to the embedded User Guide or contact us at [email protected].