Accuracy:
< 0.03%.
FRESH noise stimulus:
Available in entire frequency range within the transducer specified range (for
SF 125 - 12500 Hz). Accuracy 0.3%
Narrow Band Noise masking:
Available for each stimulus frequency.
Frequency resolution:
125 to 12500 Hz at standard frequencies
Stimulus types
•
Tone
•
Warble
•
Pulsed tone
•
Pulsed warble
•
FRESH Noise
Frequency-specific hearing assessment noise.
Consists of noise bands, with frequency-specific filter width.
The FRESH noise is filtered to obtain very steep slopes outside the passband.
Masking types
•
Narrow Band Noise
–
AC and BC
–
SF
Correlated
Correlated
•
Speech Weighted Noise
–
AC and BC
–
SF
Correlated
Correlated
•
White Noise (Wide band noise)
–
AC and BC
–
SF
Correlated
Correlated
White noise for Pure Tone masking
Conversion between displayed “effective masking level” and sound pressure level
The level of white noise used for masking of pure tones is indicated in dB of “effective masking level” in Otosuite. This
means that the sound pressure level of the power contained in a third-octave band around the presented pure tone fre-
quency will equal the attenuator setting, plus the RETSPL at the pure tone frequency, plus the noise correction factor
from ISO 389-4:1994, Table 1.
The following tables can be used to calculate the actual sound pressure level of the white noise signal for a given atten-
uator setting (Table 1), or to select the attenuator setting required to obtain a specific level in dB SPL (Table 2).
Note: As the sound pressure level of the white noise signal will be quite high even for moderate attenuator settings, a
warning sign will be displayed in Otosuite for levels above 100 dB HL.
Table 1 - Offset from Effective Masking Level to Sound Pressure Level
Frequency (Hz)
125
250
500
750
1000
1500
2000
3000
4000
6000
8000
9000
10000
11200
12500
Offset (dB)
N/A*
53
37
32
31
29
30
29
27
31
27
26
26
25
25
22
Aurical Aud
17 Technical specifications
