Q&A

Subject: Multi-band Technology in Digital Hearing Aids (1998)

From: JZ

I know that some of the companies that have a digital hearing aid (DAP or DSP) focus their promotions on the quantity of bands that the equipment uses to divide the incoming signal. Some equipments have two, three or up to seven bands to process the incoming signal before send to the speaker. Does the quantity of bands used to process the signal make a significant difference in the quality of the sound? Is an equipment with more bands a technologic advance compared with another with less? Thank you for your help. Regards, JZ

Dear J,

I don't think there is a simple answer. If an individual has an unusual pattern to a hearing loss, then multiple bands offer the possibility of a closer mirroring of that pattern. But, the vast majority of losses slope steadily downward.

Instruments today have up to 20 bands. The number of bands that are actively controlled by the digital signal processing circuits, is perhaps more important than the number of filter bands at the input to the aid. Some instruments apply signal processing to each band, and thus can reduce some noise signals without reducing the speech signals.

The nicest thing about multiple bands in the active processing circuit part of the aid is that you can set the maximum comfort levels independently for each band. Many hearing impaired individuals are quite comfortable with lower pitches while high pitched sounds can be quite sharp or piercing.

I guess the ideal solution would be to seek out a dispenser who has demonstration instruments for you to listen to and compare in the office.

ENJOY!
Solveig