Electroacoustic Measures

Question 1

What is an HA-1 coupler?

Answer 1

It simulated the size of the canal when a custom product is inserted (ITE and ITC)
Devices attached using funtak

Question 2

What is an HA-2 coupler?

Answer 2

Traditional BTE devices with earhook
Attached directly to earhook

Question 3

Can a BTE attached to an earmold be tested with an HA-1 coupler?

Answer 3

Yes

Question 4

What is a 0.4cc wideband coupler?

Answer 4

Only available on the verifit 2
Used for CIC, IIC, and RICs
Smaller cavity mimics deeper placement into canal

Question 5

What is a reference microphone?

Answer 5

Calibrates the SPL output from the test box speakers
Monitors signal intensity and automatically adjusts the speaker volume to maintain appropriate intensity

Question 6

What is a coupler microphone?

Answer 6

A measurement mic sealed into the coupler that collects the output data from the hearing aid

Question 7

What is a zwislocki coupler?

Answer 7

A coupler that is designed to better simulate the characteristics of the ear canal
Primarily used for research

Question 8

What is OSPL90?

Answer 8

Output for a 90 dB SPL input signal
Identifies the loudest possible output point the device can produce for a 90 dB input signal

Question 9

What is HFA OSPL90?

Answer 9

Calculates the average OSPL90 output for 1, 1.6, and 2.5 kHz

Question 10

What is HFA FOG?

Answer 10

Shows the average gain for 1, 1.6, and 2.5 kHz for a 50 dB SPL input

Question 11

What is reference test gain?

Answer 11

Set device to a level that does not saturate the device’s output

Question 12

What is equivalent input noise?

Answer 12

Measures the internal noise of the hearing aid
Typically, 25-30 dB SPL is acceptable

Question 13

What is total harmonic distortion?

Answer 13

Determines if the output signal contains frequencies that were not present in the input signal

Question 14

What is the directional microphone front-to-back ratio?

Answer 14

Compares output of an input signal coming from 0-degrees azimuth to an input coming from 180-degrees azimuth
The difference is the ratio
Larger differences suggest a greater directivity index

Question 15

What are the two ways that directionality is measured?

Answer 15

Noise and noise adaptive directional measure (signal pulses on/off, rapidly alternating between speakers, need to steer null towards the noise source)
Speech and noise directional measure (signal is presented from front speaker and noise is presented to rear)

Question 16

In directional microphone test, what does the dark line represent?

Answer 16

The front microphone output

Question 17

In directional microphone tests, what does the light line represent?

Answer 17

Back output at the null

Question 18

What is a telecoil measurement?

Answer 18

Compares telecoil output to microphones reference test gain output
Verifies output is the same
Identifies which position provides greater output

Question 19

What is TMFS?

Answer 19

Telecoil magnetic field simulator test
Electromagnetic signal emitted from the T

Question 20

What is SPLITS?

Answer 20

Sound pressure level for an inductive simulator measurement
The output measure of the TMFS signal
Average response from the telecoil (output)

Question 21

What is RSETS?

Answer 21

Relative simulated equivalent telephone sensitivity
The difference between the SPLITS output and the mic output when the device is set to reference test gain
Difference between the mic and telecoil output

Question 22

What does a positive RSETS mean?

Answer 22

The telecoil output is too loud and needs to be lowered

Question 23

What does a negative RSETS mean?

Answer 23

The telecoil output is too quiet

Question 24

What is SPLIV?

Answer 24

Measures output for a looped room
Measures telecoil output in a vertical position

Question 25

What is RSLS?

Answer 25

Relative simulation for loop sensitivity