Compression
A type of compression that uses different compression ratios for different input levels
What is non-linear?
Appropriate distance from patient to loudspeaker
What is 18-36 inches?
The minimum sampling rate at which a signal is sampled without introducing errors
Microphone that has equal sensitivity for all angles
Real ear measurements taken with hearing aid not on the ear
What are REUR and REUG?
Used to ensure the output is limited, and can cause distortion
What is peak clipping?
First step in real ear measurements
What is otoscopy?
OR
What is calibration?
Creates acoustic signals by electromagnetic mechanical transduction
What are receivers?
Wind, resembles reverberation, steady-state sounds, and high intensity, transient sounds
What is noise?
Used to measure the gain provided by the concha and pinna
Displays amount of gain provided for different input intensities
What is an Input-Output Function?
Distance from probe tube to eardrum
What is ~5mm?
How receivers transduce energy
What is changing from electrical energy to mechanical to acoustic energy?
Occurs because the rear port of the hearing aid contains an acoustic damper or resister
What is internal time delay?
Measured with hearing aid in and turn on
What are REAR and REAG?
Reduces low intensity environmental sounds and circuit noise without sacrificing speech intelligibility
What is expansion?
Recommended azimuth for real ear measures
What is 0 degrees?
Two different methods to modify sounds that enter a hearing aid
What are analog amplification and digital amplification?
Uses modulation detection to determine if the signal in each channel is noise
What is Gain-Reduction DNR?
Measure of SPL as a function of frequency when the hearing aid is in and turned off.
What is REOR?
Static compression properties not dependent on time
What are compression threshold, compression ratio, and compression range?
Used to convert HL thresholds to ear canal SPL
What is REDD?
When unwanted signals occur in the output of a DSP hearing aid as a result of under-sampling
What is aliasing?
Directionality feature that programs frequency channels to directional or omnidirectional independently in different frequency channels
What is split-channel directivity?
Directly shows the dB SPL at the eardrum with the hearing aid on, without referencing unaided conditions
What is REAR?