GSi TYMPSTAR 1, Service Manual

Page: 23 / 224

Noise Stimulus
The uniformity of the spectrum level of acoustic pressure for the noise signal over 20
averages measured acoustically within their respective band limits will be:
±10 dB for insert or probe type earphones
±5 dB for supra-aural type earphones
Noise Band Widths:
Low Band: 125 -1600 Hz
High Band: 1600 - 4000 Hz
Broad Band: 125 - 4000 Hz (Relative to level at 1 kHz)
Band-edges accurate to within ±15%
Roll off rate: >12 dB/Octave
Stimulus Level Control
Tone Stimulus: The transfer of reference equivalent threshold values are based on the
article; “Reference Threshold Levels For The ER-3A Insert Phone”, by Laura Ann
Wilber, Barbara A. Krueger and Mead C. Killion, J. Acoustic Soc. Am. Suppl. 1, Vol.
81 Spring 1987. GSI determined the transfer data from an IEC 711 coupler to an
ANSI HA-1 coupler. Using this data, the reference threshold values were deter-
mined for both the Ipsi and Contra insert earphones for calibration in an ANSI HA-1
2cc coupler.
Noise Stimulus: The transfer of reference threshold values was done by GSI using the
“Threshold Determination Method.” The transfer data from an IEC 711 to an ANSI
HA- 1 coupler was determined by GSI.
GSI TympStar Version 1 and Version 2 Service Manual 2 - 3
Specifications
Pressure Maximum Limits: -800 daPa to +600 daPa
Programmed Pressure Ranges:
Normal: + 200 to - 400 daPa
Wide: + 400 to - 600 daPa
Pressure Accuracy: ±10% or ±10 daPa, whichever is greater in cavities
from 0.5 cc to 5.0 cc.
Pressure Sweep Rate: 12.5 daPa/sec
50 daPa/sec
600/200 daPa/sec
Manual Sweep Rate Limit: 600 daPa/sec
Sweep Rate Accuracy: ±10%
Pressure System Leak Rate: < 1. 0 daPa/sec
(Measured at -600 and +400 daPa, while pressure servo is disabled.)
Pure Tone Stimulus
Frequencies for Contra phone and for Ipsi phone with time multiplexed
stimulus. See Table 3.
Pneumatic System
Acoustic Reflex
Activating (Stimulus)
Signal
Frequency Accuracy: ±3%
Total Harmonic Distortion :
< 5% at 500 Hz, 85dBHL
< 5% at 1000Hz - 3000Hz, 100dBHL
< 5% at 4000Hz, 75dBHL
< 10% at the maximum dBHL settings
Reference:
ANSIS3.39-1987
Section 7.5.2.2 Frequency Accuracy
Section 7.5.2.3 Harmonic Distortion