Harmonicity Meter 1.20

Measure the Harmonic to Noise Ratio (Harmonicity) from your microphone.

Harmonicity is a measure of the sound energy in the harmonics relative to the rest of the spectrum. It varies with age, gender, and the vowel pronounced. Higher harmonicity values indicate a purer sound, while lower jitter and shimmer values also indicate a purer sound.

This meter is designed to be used with a continuous and consistent sound, such as pronouncing a vowel or a tone from a speaker/instrument. Rapidly changing tones/sounds will yield nonsensical output.

FOR INDICATION ONLY. Harmonicity can vary based on the proximity of the source to the microphone. Microphone sensitivity varies with frequency and among devices. Even within scientific literature, consistency in absolute reported values is challenging to find.

Jitter measures the frequency variation of the sound, displayed as a relative percentage.

Shimmer measures the amplitude variation of the sound, displayed as a relative percentage. The app will start measuring only when a sound is detected.

Averaging starts after 0.7s, where the app averages Harmonicity, Jitter, Shimmer, and frequency values until the sound stops. The last 0.7s of data is then removed from the averaged values.

Musical Note feature converts the detected frequency into a note based on Western 12-tone equal temperament for instrument tuning purposes.

Pause button is useful in noisy environments when measurement does not auto-stop.

FFT Spectrum autoscales Sound Intensity between 0 and 2 kHz with a range of 100 Hz to 2 kHz for fundamental harmonic frequency detection.

Technical bit: The fast Fourier transform (size 8192) is carried out on the last 0.74s of data to generate a frequency spectrum (0 to 5.5 kHz with 1.35Hz resolution). This spectrum is windowed between 100 and 4 kHz with linear fall-offs to zero at 50 and 5 kHz. The fundamental frequency is determined through polynomial fitting to peaks. The harmonic energy is calculated from the sum of the FFT signal at the harmonic frequency plus 8 Hz on either side. The remaining FFT signal represents noise. The Harmonicity ratio, displayed in decibels, indicates the ratio of harmonic to noise energy.

For more in-depth technical information, visit the website.