Real-Ear Measurements 161
*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. See Section 2.5.1.4 for more details.
*SIGNAL SKEW—The number of samples from when the speaker emits the
signal source to when the FP35 microphone reads and analyzes it. See Section
2.5.1.5 for details.
*OUTPUT SELECT—The external source devices enabled in the measure-
ment screen. The AUTO and SPEAKER selections enable only the speaker jack.
EARPHONE enables only the earphone jack. BOTH enables both the speaker
and the earphone jack. See Section 2.5.5 for details.
SPEAKER—The sound field speaker selection. Choose to use the FP35 analyz-
er’s INTERNAL speaker or an attached EXTERNAL speaker.
*LEVELING SOURCE—The amplitude used for leveling the sound field speaker.
*IMPULSE REJ—Status of impulse rejection, which rejects noise in the testing
environment. See Section 2.5.6.
*RMS ANALYSIS—The type of RMS analysis used for the measurements.
Choose AUTO (estimated RMS) or NONE. See Section 2.5.3 for details.
*DISTORTION—The type of harmonic distortion of a single tone or of a normal
sweep curve. Choices are 2ND, 3RD, TOTAL (2ND + 3RD), or OFF.
Note: Distortion is not normally measured in real-ear due to the noise levels in
the test environment being seen as distortion.
*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 harmon-
ic 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.
*IM FREQ DIFF—The distance between the primary and secondary frequency
in the intermodulation distortion measurement. See Section 2.5.2.2 for more
details.
* These menu items are only available when the USER LEVEL is set to
ADVANCED mode. See Section 2.3.2 for details.
