Enhancement of alaryngeal speech by adaptive filtering

Artificial larynxes enable adequate communication for people who are unable to use their larynxes. However, the resulting speech has an unnatural quality and is significantly less intelligible than normal speech. One of the major problems with the widely-used transcutaneous artificial larynx (TAL) is the presence of a steady background noise due to the leakage of acoustic energy. In this study, a novel adaptive filtering architecture was designed and implemented for the purpose of removing the background noise. Perceptual tests were conducted to assess speech from two laryngectomees and two normal speakers using the Servox TAL, before and after processing by the adaptive filter. Results from the perceptual tests indicate a clear preference for the processed speech, and spectral analysis reveals a significant reduction in the background source radiation.