Exam 1 hearing aids

The _______is a critical component of a hearing aid that converts acoustic energy to electrical energy.

microphone

Which component of a hearing aid amplifies the electrical signal?

amplifier

Individuals often report higher satisfaction when they can use and maintain their hearing aids effectively.

True

What is the main goal of hearing aid orientation?

To provide users essential information on how to use and care for their hearing aids.

Earmolds help provide an ______ seal necessary for sound delivery.

Acoustic

The ______ takes the amplified electrical signal and converts it back into an acoustic signal for the ear.

Receiver

Studies have shown that around _____ of the information provided during hearing aid orientation is forgotten within six weeks.

50%

A hearing aid cannot _______ but can assist in hearing better.

Restore normal hearing

True or False: Hearing aids can completely restore normal hearing.

False

True or False: All hearing aids come with a Telecoil as a standard feature.

False

The presence of a sine wave which wasn’t present in the input, but is present in the output of the digital signal due to an error in digitizing signals is called

Aliasing

A ____ is the smallest unit of digital information and can have ____ values corresponding to the states at its input.

bit, 2

Hearing loss results in abnormal loudness growth and a reduced dynamic range, which we call

recruitment

What are the big six hearing aid companies?

Starkey, Phonak, Signia, Oticon, Widex, and ReSound

The ______ should be 2 times higher than the highest frequency component you want represented in the signal.

Nyquist Rate

What are the three types of feedback

Acoustic, electrical, mechanical

Name the two main approaches to feedback cancellation.

Notch filtering, phase cancellation

True or False: A hearing aid will feedback if the forward gain is less than the leakage attenuation.

false

§low-pass filter input signal with upper cutoff frequency at ½ the sampling frequency.

anti-aliasing filter

Difference between digital signal and original acoustic signal

Quantization error

addition of a tonal sound to the output by the hearing aid in an attempt to phase cancel

Entrainment

keeping quiet sounds inaudible

expansion

Tolerance for Max SPL90

no more than +3dB

Tolerance for HFA OSPL 90

± 4dB

HFA Full on gain tolerance

+/- 5dB

Total Harmonic distortion frequencies and intensities

70 dB at 500 Hz

70 dB at 800 Hz

65 dB at 1600 Hz

Total harmonic distortion tolerance

no more than +3%

When will feedback happen?

When forward gain is more than leakage attenuation

Equivalent input noise tolerance 

no more than +3dB

TK stays constant, gain and MPO change

input compression

Mpo stays constant, tk changes

output compression