Audiometer Specifications
Technical specifications for the Sound Scouts Automatic Audiometer, including test protocols and RETSPL values for supported headphones.
Test Protocols
| Parameter | Value |
|---|---|
| Testing protocol | Screening (500, 1000, 2000, 4000 Hz) at 20 dBHL; Custom protocol (frequency and levels) |
| Threshold seeking method | Modified Hughson Westlake |
| Attenuation | 5 dB step size |
| Tone type | 4 burst pure tone |
| Response window after tone | 100 ms after tone onset, and 2000 ms after tone offset |
| Pre-tone waiting period | Variable: 2500 ms–5000 ms |
| Tone duration | 235 ms |
| Rise/fall time | Rise/fall times of 35 ms, separated by 235 ms |
Reference Equivalent Threshold Sound Pressure Level (RETSPL)
Values for headphones calibrated on an IEC 60318-1 artificial ear. Application force should be that achieved by separating the left and right headphones by 145 mm.
| Frequency (Hz) | Sennheiser HD 300 | Sennheiser HD 400S | Telephonics TDH39 | RadioEar DD65v2 |
|---|---|---|---|---|
| 125 | 30.5 | 30.5 | 45 | 30.6 |
| 250 | 13.7 | 13.7 | 25.5 | 16.9 |
| 500 | 6.7 | 2.4 | 11.5 | 7.8 |
| 1000 | 0.4 | −7.3 | 7 | 5.3 |
| 2000 | 1.4 | −0.7 | 9 | 2.3 |
| 3000 | −3.7 | −3.7 | 10 | 2 |
| 4000 | −1.1 | 1 | 9.5 | 9.3 |
| 6000 | 3.8 | 3.1 | 15.5 | 20.8 |
| 8000 | 19 | 18.5 | 13 | 20.9 |
