GSi 61 - Page 66

Grason-Stadler GSI
®
61 CLINICAL AUDIOMETER
Bandwidths for Narrow Band Masking Sounds
(Pass Band Upper and Lower Frequency Limits at 3 dB Points)
Center Frequency, Hz
Lower Limits, Hz Upper Limits Hz
125 105 -111 140 - 149
250 210 -223 281 - 297
500 420 -445 561 - 595
750 641 -668 842 - 892
1000 841-891 1120-1190
1500 1260-1340 1680-1780
2000 1680-1780 2240-2380
3000 2520-2670 3370-3570
4000 3360-3560 4490-4760
6000* 5050-5350 6730-7140
8000* 6730-7130 8980-9510
12000* 10092-10570 13500-14275
* Due to the limitations of the existing couplers and artificial ears, acoustic measurements are
not required.
Bandwidth for Narrow Band Masking Sounds (High Frequency)
(Pass Band Upper and Lower Frequency Limits at 3 dB Points)
Center Frequency Hz
Lower Limits Hz Upper Limits Hz
8000 6730-7130 8980-9510
9000 7570-8020 10100-10700
10000 8410-8910 11220-11890
11200 9420-9980 12570-13320
12500 10510-11140 14030-14870
14000 11770-12470 15710-16650
16000 13450-14250 17960-19030
18000 15138-16042 20196-21413
20000 16820-17815 22440-23792
Bone Vibrator (B71) Calibration Values for Non-occluded Test Ear
Mastoid Placement (ANSI 3.43 and ISO 7566)
Frequency 250 500 750 1000 1500 2000 3000 4000 6000 8000 Speech*
Radioear B71 with
67.0 58.0 48.5 42.5 36.5 31.0 30.0 35.5 40.0 40.0 55.0 dB re: 1 N
non-occluded ear
Notes: These values were obtained with 30 to 35 dB effective masking by air conduction to the
non-test ear.
The above values apply for the mastoid position using the Bruel and Kjaer type 4930 artificial
mastoid, having manufacturer’s serial numbers of 526226 or higher, and type B71 bone vibrators
used with a P-3333 headband.
These values are from ANSI 3.43 and ISO 7566.
N
o standard reference equivalent threshold level for speech has been established for bone
vibrators.
The reference level used for the calibration of speech is 12.5 dB above the 1000 Hz level or at
a force level of 51.2 dB re: 1 N.
The values in the table are
b
ased on 0 dB HL settin
g
s.
* Tentative
1.
2.
3.
4.
5.
5-4
,
, ,,
1761-0100 Rev. B