Ian C Bruce, Shahab U Ansari, Harjeet S Bajaj, and Kamran Mustafa (2004)
Multiband compression and contrast-enhancing frequency shaping in hearing aids
Canadian Acoustics, 32(3):62-63.
A hearing-aid amplification scheme that uses a formant-tracking algorithm and time-varying filter to produce improved contrast enhancement between formants is presented. The combination of contrast-enhancing frequency shaping (CEFS) amplification and multiband compression in a single frequency-domain filterbank implementation is also studied. CEFS compensates for the broadened tuning curves and elevated thresholds of unimpaired ear by adjusting the relative amplitudes of the formats without distorting the spectral envelope between the formants. Multiband compression, on the other hand, has been utilized in hearing aids to compensate for the reduced dynamic range of the impaired ear.