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90 FONIX FP35 Hearing Aid Analyzer
Custom Menu
Press [NEXT] from the Advanced Menu to enter the Custom Menu.
*OUTPUT LIMIT—Level of output limiting, which shuts off the source when
the measured signal exceeds the limit set here. Choices are: OFF; 80-140 dB
SPL. This is usually used only for real-ear type measurements.
*WARBLE SOURCE—The warble rate in pure-tone signals. Warble is usually
used in sound field speaker measurements to reduce problems caused by stand-
ing waves. This is usually turned off for normal coupler measurements. See
Section 2.5.1.4 for more details.
*SIGNAL SKEW—The number of samples from when the signal source leaves
the speaker to when the FP35 analyzes it. See Section 2.5.1.5 for details.
SPEAKER—Selected speaker output. INTERNAL uses the internal speaker jack,
which is usually connected to the internal sound chamber. EXTERNAL uses the
external speaker jack, which can be connected to an external sound chamber.
AUTO uses the internal jack for sound chamber measurements and the external
jack for real-ear measurements.
*OUTPUT JACK-Select which external source devices are enabled in the cou-
pler screens. SPEAKER enables only the speaker jack. MONO EAR enables only
the left channel of the earphone jack. STEREO EAR enables both channels of
the earphone jack. ALL ON enables the speaker jack and both channels of the
earphone jacks. See Section 2.5.5 for details.
LEVELING SOURCE—The amplitude used for leveling the speaker. This is use-
ful if you need to level with the chamber door open, and you don’t want to use
the loud default level of 90 dB SPL. Choose between 60 and 100 dB SPL.
*IMPULSE REJ—Status of impulse rejection, which rejects noise in the testing
environment. See Section 2.5.6.
*DIST 90 dB RULE—Harmonic distortion measurements are generally made
only when the source of the test signal is below 90 dB SPL. To measure har-
monic distortion at 90 dB SPL or higher, turn this rule OFF.
*DISTORTION SWEEP—The frequencies used in the intermodulation distortion
measurement. NORM uses 1/12 octave frequencies to the nearest 100 Hz. FAST
uses 1/3 octave frequencies to the nearest 100 Hz. FULL uses every 100 Hz fre-
quencies available.
*DIST SWEEP END—The last frequency tested when performing an IM distor-
tion sweep. If the selected frequency is less than or equal to the first primary
frequency in the IM distortion sweep, only the primary frequency will be tested;
there will be no IM distortion sweep.