Psychoacoustic Analysis

dBSONIC PSY includes the following metrics:

• Loudness
• Sharpness
• Roughness
• Fluctuation Strength

These algorithms are based on the sophisticated psychoacoustic parameters of the CORTEX Acoustic Workstation. They reflect many years of experience in industrial sound design and hearing based noise analysis. In combination with the dBSONIC high resolution spectrogram displays a powerful analysis tool is provided.

Loudness

The loudness analysis calculates all spectral and temporal parameters that contribute to the perceived loudness. Stationary signals are analysed in accordance with DIN 45631 and ISO 532 B, by including nonlinear post-masking algorithms, non stationary signals can also be analysed. In order to calculate further psychoacoustical parameters like roughness data are stored with a temporal resolution of 2 ms. Loudness calculation can be used for all situations, where the human hearing system is the final receiver. E.g.: Two vacuum cleaners may have different loudness, although their A-weighted sound pressure level is the same.

Sharpness

Sharpness is an indication of the spectral balance between low and high frequencies. The more high frequencies a signal contains, the higher its sharpness is.

Fluctuation Strength

Spectral analysis of roughness and fluctuation strength yields additional data for time-varying signals. Almost all technical signals show modulations and fluctuations produced by periodic or stochastic processes.
Fluctuation strength is the perceptual quantity for low-frequency amplitude modulations. When the modulation frequency is below 20 Hz the ear will notice each single event. Psychoacoustic tests showed a maximum sensitivity for modulation frequencies around 4 Hz. The unit for fluctuation strength is Vacil (1 Vacil = 100 cV).

Roughness

Amplitude- and/or frequency modulations with modulation frequencies above 20 Hz produce a sensation that is different from fluctuation strength. The ear is no longer able to follow each individual period, but still detects variations in the temporal envelope. Fast modulations are called "warble", "twitter", "buzz". The ear is highly sensitive to fast modulations for modulation frequencies around 70 Hz. The unit for roughness is Asper (1 Asper = 100 cA). Sharpness, loudness spectrum, roughness spectrum and fluctuation strength spectrum are the fundamental parameters for the calculation of annoyance or sound quality.