Paired Inserts: -10 dB HL to 95 dB HL
Channel 2
Masking Level Range
Narrowband Noise (Calibrated in effective masking)
Maximum dB HL is 15 dB below tone
Speech Noise (calibrated in effective masking):
Air Conduction -10 dB HL to 95 dB HL (DD45)
Bone Conduction -10 dB HL to 50 dB HL (mastoid)
-10 dB HL to 40 dB HL (forehead)
Sound Field: -10 dB HL to 85 dB HL
White Noise:
Air Conduction -10 dB HL to 95 dB HL (DD45)
Bone Conduction -10 dB HL to 60 dB HL (mastoid)
-10 dB HL to 50 dB HL (forehead)
Sound Field -10 dB HL to 80 dB HL
Frequency Range
Narrowband Noise 3 dB down bandwidth, 1/3 octave minimum; ½ octave maximum of
test signal
Speech Noise Equal energy per frequency 100 to 1,000 Hz with a 12 dB/octave
roll-off from 1,000 to 6,000 Hz
White Noise 125 Hz and 12,000 Hz with constant bandwidth
Input Specifications Ext. CD 7mVrms at max. gain for 0dB reading; input impedance 47kOhm
Talk Forward 100uVrms at max. gain for 0dB reading; input impedance 3.2kOhm
Output Specifications Headphones 7Vrms at 10 Ohm load; 60-20,000Hz -3dB
Insert Phones 7Vrms at 10 Ohm load; 60-20,000Hz -3dB
Bone 7Vrms at 10 Ohm load; 60-10,000Hz -3dB
Sound Field 7Vrms at min. 2kOhm load; 60-20,000 kHz -3dB
Monitor 2x 3Vrms at 32 Ohm/1.5Vrms at 8 Ohm load; 60-20,000Hz -3dB
Free Field Power Amplifier and Speakers-With an input of 7 Vrms-Amplifier and loudspeakers must be able
to create a sound pressure level of 100 dB at a distance of 1 meter and meet the following
requirements:
Frequency Response 125-250Hz, +0/-10
250-4000Hz +3 dB
4000-6300Hz +5 dB
Total Harmonic Distortion 80 dB SPL <3%
100 dB SPL <10%
Special Tests ALT (ABLB)*: Tone alternating between Channel 1 and Channel 2: Channel 1 is 400
msec ON, 400 msec OFF followed by Channel 2, 400 msec ON, 400
msec OFF.
SISI*: A level increment is added to a tone in the selected channel for 200
msec, every 5 seconds. The HL increments are in 1, 2 or 5 dB.
High Frequency:* Pure tone testing in the frequency range of 8,000 Hz to 20,000 Hz
using circum-aural headphones
TEN*: TEN masking noise will be presented to the test ear. Pure tone stimuli
between 500 and 4000 Hz may be used at 1, 2, or 5 dB increments to
obtain TEN thresholds.
QuickSIN*: Six (6) sentences with five (5) key words per sentence are presented
in four-talker babble noise. The sentences are presented at pre-
recorded signal-to-noise ratios. The SNR’s used are 25, 20, 15, 10, 5,
and 0.
BKB-SIN*: 18 List Pairs. The sentences are presented at prerecorded signal-to-
noise ratios that decrease in 3-dB steps. Each list in the pair is
individually scored, and the results of the two lists are averages to
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