# Experimental Study on Noise-Reduced Propagation Characteristics of the Parametric Acoustic Array Field in a Neck Phantom

## TL;DR

This study explores a new method using parametric acoustic arrays to reduce noise and improve speech quality for laryngectomy patients.

## Contribution

A novel PAA-based voice source is proposed for laryngectomy patients, showing reduced noise and natural speech characteristics in a phantom model.

## Key findings

- Difference-frequency signals in the phantom's trachea closely matched the designed glottal waveform (Pearson r = 0.9438).
- PAA reduced radiation noise by 23 dB compared to traditional electrolarynx devices (p < 0.0001).
- The PAA shows potential for improving speech rehabilitation in laryngectomy patients.

## Abstract

The electrolarynx (EL) is a common device for voice reconstruction in laryngectomy patients, but its mechanical sound source generates significant radiation noise, affecting the naturalness and acceptability of the speech. The parametric acoustic array (PAA), which produces directionally propagated difference-frequency sound waves, presents a promising alternative for creating a more natural glottal-like voice source in the trachea while reducing radiation noise. In this study, we developed a tissue-mimicking phantom to simulate human neck tissue and used a single-transducer-based PAA platform to generate modulated ultrasound signals with glottal waveform characteristics. Ultrasonic microphones captured sound signals fromthe trachea and surrounding air, and signal processing was used to isolate the difference-frequency signals. The results demonstrated that difference-frequency signals were successfully detected in the phantom’s trachea, with time-domain waveforms and frequency spectra closely resembling the designed glottal waveform (Pearson correlation coefficient = 0.9438). Additionally, radiation noise produced by the PAA was significantly lower (23 dB, p < 0.0001) compared to the traditional EL. These findings demonstrate the potential of PAA for voice source reconstruction in laryngectomy patients and suggest its capacity to enhance speech rehabilitation outcomes. Further research is required to refine the frequency range and evaluate clinical applicability.