otometrics AURICAL Aud, Reference Manual

Page: 121 / 136

Accuracy of sound level
Entire level range (AC): 125 to 5000 Hz: ±3 dB, 5000 to 12500 Hz: ±5 dB
Entire level range (BC): 250 to 5000 Hz: ±4 dB, 5000 to 8000 Hz: ±5 dB
The reference conditions for the specification of frequency response and sound pressure level depend on the type of audi-
ometer. AURICAL Aud can be calibrated as either a “corrected” (Type AE) or “uncorrected” (Type A) speech audiometer:
Type AE calibration:
• The output sound pressure level and frequency response are specified in terms of free-field equivalent sound pressure
level.
• The loudspeaker output is specified as measured under free-field conditions, at 1 m distance, and on the axis of the
loudspeaker.
• Bone vibrator output is not corrected to obtain a free-field equivalent sound force level; uncorrected output is pro-
duced (please see below under “Type A”).
• Calibration of speech signals is performed using either a 1 kHz pure tone (earphones) or 1 kHz warble tone (loud-
speakers).
Type A calibration:
• The output sound pressure level and frequency response are specified in terms of coupler level. See table below for
coupler/ear simulator used.
• The loudspeaker output is specified as measured under free-field conditions, at 1 m distance, and on the axis of the
loudspeaker.
• Bone vibrator output is not corrected to obtain a free-field equivalent sound force level; uncorrected output meas-
ured by an artificial mastoid (IEC 60318-6) is produced.
• Calibration of speech signals is performed using either a 1 kHz pure tone (earphones) or 1 kHz warble tone (loud-
speakers).
Transducer type Coupler/ear simulator
Supra-aural earphone IEC 60318-3
HDA200/HDA300 IEC 60318-1
Insert phone IEC 60318-5
Attenuator
1 or 5 dB step resolution over the entire range.
HL Range
The maximum output levels from AURICAL Aud depend on the actual sensitivity of the individual transducers, and they
will be slightly different for each unit. However, the minimum requirements from IEC and ANSI standards are fulfilled for
all units.
They are specified in the following.
Otometrics - AURICAL Aud 121
13 Technical specifications