GSi 61 - Calibration Reference Levels

Chapter 5 - Routine Maintenance
Calibration Reference Levels
It is recommended that each GSI 61 receive a thorough calibration certification once a year. If
periodic checks are also desired, the tables in this section provide the SPL values per frequency
for each transducer. If the measured values are not within ± 5 dB at 125, 6000, 8000 and 12,000
Hz in the earphones, the GSI 61 should be scheduled for immediate maintenance.]
Sound Pressure Levels for Pure Tones with TDH 50PEarphones
SPL values with TSH 50P earphones for 70 dB HL setting
Frequency 125 250 500 750 1000 1500 2000 3000 4000 6000 8000 12000 Speech
IEC 303
117.5 96.5 83.5 78.5 77.5 77.5 81.0 79.5 80.5 83.5 83.0 87.5* 90.0
IEC 318
115.0 97.0 83.5 79.0 77.5 77.5 79.0 81.5 82.0 86.0 85.5 82.5* 90.0
*Interpolated
Note: The 125 Hz through 8000 Hz values are based on ANSI S3.6-1989 and ISO 389-1991
Standards.
Reference Levels for Pure Tones with E•A•R Tone Earphones
SPL values with the E•A•R Tone Earphones for 70 dB HL setting
Frequency 125 250 500 750 1000 1500 2000 3000 4000 6000 8000 Speech
IEC 126
96.0 84.0 75.5 72.0 70.0 72.0 73.0 73.5 75.5 72.0 70.0 82.5
IEC 711
98.0 87.5 79.5 76.0 75.5 79.5 81.5 83.0 85.0 86.0 85.5 88.0
Note: The 125 Hz through 8000 Hz values are based on ISO 389, Amendment 1.
Effective Masking Values for Pure Tones - ISO 8797
Narrow band noise SPL value for 70 dB HL setting
Frequency 125 250 500 750 1000 1500 2000 3000 4000 6000 8000 12000 Speech Noise
IEC 303
121.5 100.5 87.5 83.5 83.5 83.5 87.0 85.5 85.5 88.5 88.0 92.5* 90.0
IEC 318
119.0 99.0 87.5 84.0 83.5 83.5 85.0 87.5 87.0 91.0 90.5 87.5*
*Interpolated
Note: For narrow band noise, the level control is calibrated in dB of effective masking. The
SPL in each one-third octave band centered at each frequency is calibrated to a level 3 dB
above the standard reference level for this frequency.
5-3
1761-0100 Rev. B