How Hearing Aids Work
The primary function of a hearing aid is to facilitate auditory communication between an individual with hearing loss and the party, or parties with whom they’re conversing. Hearing aids accomplish this task by receiving sound signals extant in the surrounding environment, identifying and magnifying important speech information, suppressing background noise and outputting the precisely modified sound directly into the wearer’s ears.
Common microphone types include directional, omni-directional and a hybrid of the two types that can swap back and forth depending on the current listening environment. The primary function of a hearing aid microphone or transducer is to convert the analog sound signal it receives into an electrical signal that can be understood by the processor. The newly converted electrical signal is then converted to a digital signal and sent to the digital signal processor.
Digital Signal Processor DSP
The DSP is a miniature, digital microprocessor that continually samples the incoming sound signal from the microphone and applies a specific algorithm that precisely matches the sound signal to the individual’s hearing prescription. The modified digital signal then enters the amplifier for the next step in the process.
The amplifier is typically incorporated into the IC along with the DSP. The amplifier magnifies the digitally modified audio signal by increasing the gain in those frequency channels necessary reach the wearer’s minimum hearing thresholds and hear sounds clearly again.
The receiver is the output end of a hearing aid. It transforms the electrical signal back into an analog sound that the brain can hear, identify, and understand.