IS 11024 : 1984 Specification for Standard Reference Zero for the Calibration of Pure-tone Bone-conduction Audiometers and Guidelines for its Practical Application

1 Scope

1.1 This standard specifies This data applicable to thecalibration of bone vibrators for pure-tone bone-conductionaudiometry:

a) Reference equivalent threshold force levels (RETFL),corresponding to the threshold of hearing of young otologicallynormal persons (see 2.9 and 2.10 ) by bone-conduction audiometry.RETFL is the alternating force level transmitted to a mechanicalcoupler of specified characteristics, see 3.2.3, by a vibrator whenapplied to the mechanical coupler under stated conditions of testand when energized at the level corresponding to the normalthreshold of hearing for mastoid placement.

NOTE - Corresponding values for forehead placement of thevibrator are under development for ultimate inclusion in thisstandard. Provisional values are included for information inAppendix C.

b) Essential characteristics of the bone vibrator and of itsmethod of coupling to a person under test and to the mechanicalcoupler.

c) Essential characteristics and datum level of the maskingnoise applied to the non-test ear.

2 References

IS 2 :1960Rules for rounding off numerical values

IS 10565 :1983Specification for diagnostic audiometers

IS10779Provisional reference coupler for thecalibration of earphones used in audiometry

IS 1885 : Part 3 : Sec5 Electrotechnical vocabulary:Part 3 Acoustics, Section 5 Speech and hearing

IS 4755 :1968Reference zero for the calibration of pure-toneaudiometers

IS 6964 :1973Octave, half-octave and third-octave bandfilters for analysis of sound and vibrations