1. TEST BOX ANALYSIS & ANSI
 In the United States, the manufacture and
dispensing of hearing instruments is
regulated by the Food and Drug
Administration.

2. TEST BOX ANALYSIS & ANSI
 The are no ANSI standards for directional
microphones—only for proper placement
orientation of a directional microphone hearing
instrument during the analysis.
 The is no ANSI standard for battery current
drain. However, it is required that the battery
drain be measured at the reference test gain.

3. TEST BOX ANALYSIS & ANSI
 Hearing instruments must pass certain
performance parameters. These
parameters are defined by the American
National Standards Institute (ANSI).

4. TEST BOX ANALYSIS & ANSI
 The International Electroacoustical
Commission (IEC) is also used to
establish hearing instrument parameters
not defined by ANSI (or required) by the
FDA.

5. TEST BOX ANALYSIS & ANSI
The key difference between ANSI and IEC
is that all electroacoustic measurements
are measured in a 2cc coupler while IEC
measurements are performed in an ear
simulator.

6. TEST BOX ANALYSIS & ANSI
 Hearing Instrument Specialist perform a
test box analysis which meets ANSI
standards—not a manikin or ear simulator.

7. TEST BOX ANALYSIS & ANSI
 Two primary couplers are used in the test box
analysis of the majority of hearing instruments
dispensed in the United States. They are:
1. The HA-1 used primarily for Custom shell hearing
instruments
2. The HA-2 used primarily for BTE style hearing
instruments.

8. TEST BOX ANALYSIS & ANSI
 Test boxes require two microphones to
measure hearing instrument
performance.
1. A control microphone—to monitor the inside
box environment.
2. A reference microphone--to be placed next to
the hearing instrument microphone.

9. TEST BOX ANALYSIS & ANSI
 Many test boxes now use a swept
broadband stimulus signal.
 The frequencies presented are received
by the hearing instrument and the
reference microphone of the test box.

10. TEST BOX ANALYSIS & ANSI
 A Fourier Transform analysis is then made
by the test box to determine the specific
frequencies coming through the hearing
instrument.

11. TEST BOX ANALYSIS & ANSI
High frequency average gain (HFA) and
the frequency range are two important
factors when selecting hearing instruments
for patient/client benefit.
See page 81 of Dillon to summarize these
calculations.

12. TEST BOX ANALYSIS & ANSI
Other test box measures include:
 Gain by frequency response
 Output saturation sound pressure level
(OSPL)
 Harmonic distortion

13. TEST BOX ANALYSIS & ANSI
 Gain by frequency response is measured
with a 60dbSPL input level.
This represents the amount of gain/volume a
hearing instrument posses with a 60dbSPL level
input into it.

14. TEST BOX ANALYSIS & ANSI
Gain of a hearing instrument is important
in providing enough amplification to create
audibility of sound to the patient/client.

15. TEST BOX ANALYSIS & ANSI
 Output Saturation Response Level (OSPL)
Measures the maximum sound pressure level
generated by the hearing instrument. It is
performed with a 90dbSPL input into the hearing
instrument.

16. TEST BOX ANALYSIS & ANSI
The hearing instrument output information
is important for patient comfort with the
electroacoustic performance of the hearing
instrument.

17. TEST BOX ANALYSIS & ANSI
 Equivalent input noise is a measurement
taken of any noise generated by the
hearing instrument itself. The test box
only listens it does not present a signal.
Note: This requires that the testing area be in a
very quiet environment.

18. TEST BOX ANALYSIS & ANSI
 Harmonic distortion is the measurement of
artifacts in the “clear” electroacoustic
performance of a hearing instrument. All
amplifiers have measureable distortion.
However, they must be within the FDA
guidelines for hearing instrument
manufacture.

19. TEST BOX ANALYSIS & ANSI
Harmonic distortion is measured at the
reference test gain setting of the hearing
instrument.
It is then presented with a 70dbSPL pure
tone signal to measure the harmonic
distortion of the hearing instrument.

20. TEST BOX ANALYSIS & ANSI
 Compression measurements are also
made during test box analysis. We will
cover much more regarding compression
next semester.

21. TEST BOX ANALYSIS & ANSI
NOTE: A nice description of methodology
for ANSI test box analysis is found on
pages 186 through 191 in Vonlanthen.