Amplification and Assistive Devices (AAD)
Instructional Level: Advanced
Some frequency transposition and all frequency compression methods adhere to an untested assumption that spectral features of high-frequency speech cues need to be preserved or replicated after lowering. Consequently, recommendations for optimizing parameter selection have focused on maximizing input bandwidth or maximizing the frequency separation between key speech contrasts. On the contrary, my research suggests that preserving temporal modulation from the original speech at the auditory periphery will be best for the perception of frequency-lowered speech.