HAT 5 Test Box

Question 1

What is a test box?

Answer 1

A way of assessing hearing aid performance

Question 2

What connects hearing aid to test box?

Answer 2

2 cc coupler

Or

Occluded ear simulator

Question 3

Full on gain (fog) is measured at what intensity?

Answer 3

60dBSPL

Question 4

What measurements are takes for full on gain (FOG)? (3)

Answer 4

Full on gain at 1kHz in dB

Max gain at peak of curve on graph

High frequency average (HFA) (average of 1kHz, 1.6kHz & 2.5kHz)

Question 5

How do you measure OSPL 90 in a test box?

Answer 5

Full frequency sweep at 90dBSPL

OSPL90 is output taken at 1.6kHz (answer in dBSPL)

Rule of thumb - ULL +10dB = OSPL90

Question 6

How is reference test gain measured?

Answer 6

Frequency 1.6kHz (ref test freq)
Intensity 60dBSPL
VC set 15dB lower than OSPL90
Test box generates a full freq sweep

*take 75 off OSPL 90

Question 7

What is distortion?

Answer 7

Distortion caused by components in aids add something to original signal, should be kept to a minimum, depends on type & level

Question 8

Name 3 types of distortion?

Answer 8

Intermodulation distortion

Harmonic distortion

Equivalent input noise level