Method for analyzing personalized telephone speech in quiet and noisy environments in normal-hearing and hearing-impaired listeners

Integrated digital signal processing in telephones allows for sound personalization algorithms directly in the devices. In the current study, a non-linear, frequency-dependent algorithm for adjusting telephone signals was evaluated with normal-hearing and hearing-impaired listeners under controlled acoustical conditions. Listeners adjusted the preferred output level and spectrum via a user interface on a touch screen during a phone call in quiet and in a noisy environment. Large individual differences of preferred output spectra were observed. Higher output levels in noisy than in quiet environments were observed for all listeners. No clear trend was observed for the preferred spectral processing when changing from quiet to noisy environments, indicating that a user-adaptive spectral optimization is required as a user-independent solution often would not match different types for individually optimum trade-off between speech intelligibility and sound comfort.