Frye Electronics FONIX COLT Audiometer
41
For either method, the Hearing Aid Simulator should be set to the “Off” position. Using live
or recorded speech materials, start at MCL and gradually increase the hearing level until the
patient indicates that the desired level is reached. In addition to asking the patient to tell you
when the sound has reached the desired level, keep a careful eye on the patient, watching for
involuntary signs of discomfort. The moment you have any indication of discomfort, turn
the hearing level down and discontinue presentation, making note of the level that caused
the discomfort. You never want the hearing aid to reach this level.
For speech tests of comfort/discomfort, the measured UCL, LDL, or HCL can roughly be
converted to 2cc-coupler SPL by adding 15 dB to the HL level you do not want the hearing aid to
exceed. Choose a hearing aid whose SSPL 90 does not exceed the resulting SPL value.
A more accurate way to choose the SSPL 90 is to measure comfort/discomfort levels for fre-
quency-specific signals, such as pulsed warble-tones. Convert the dB–HL values you obtain
to 2cc-coupler SPL values by adding the numbers in Table 5.2.2 to your HL values. Choose a
hearing aid whose SSPL 90 values do not exceed these SPLs.
Table 5.2.2: To convert from dB HL to 2cc-coupler dB SPL, add these dB values to the
measured dB HL values for each frequency measured.
*
FREQUENCY
250
500
750
1k
1.5k
2k
3k
4k
6k
8k
ADD
15
8
6
3
2
6
5
1
-2
-4
*
These measurements use the Colt's tone screen
