Calibration Procedure; Service, Adjustment And Repair - Interacoustics AC40 Service Manual

AC40 Service Manual

Calibration Procedure

Service, adjustment and repair

Annual calibration (ANSI/ASA S3.6)
The calibration procedure will validate all relevant performance requirements given in ANSI/ASA S3.6. After the
audiometric equipment has been submitted for calibration, a calibration certificate showing the values recorded
must be filled out, signed and dated by the technician, demonstrating that the instrument conforms to all relevant
requirements given in this standard.
NOTE It is considered good practice to perform annual checks of the audiometric test room's noise level as part of annual
calibration using the applicable table per ANSI/ASA S3.1 American National Standard Maximum Permissible Ambient Noise
Levels for Audiometric Test Rooms to ensure that audiometer performance will not be affected by any changes in the
audiometric test room's noise levels.
Annual calibration (IEC 60645-1)
A basic calibration shall be performed by a competent laboratory. The procedure shall be such that, after the
audiometric equipment has been submitted for a basic calibration, it shall meet the relevant requirements given in
IEC 60645-1.
When the instrument is returned after basic calibration, it should be checked in accordance with procedures
outlined in 12.3 or 12.4 before being put back into service.
It is recommended that a calibration check label be attached to the equipment, giving the date on which the next
calibration is due.
Equipment needed to perform audiometer calibrations
1. Type 1 sound level meter – Octave band filter set (1/3 octave, range of minimum 125 Hz to 16000 Hz)
must meet Type 1 sound level meter (ANSI S1.4). Sound level meters to be checked before use with a
calibrator.
2. Mechanical Coupler (used for bone conduction calibration) – B&K 4930 Artificial Mastoid – or other
mechanical coupler. Must meet ANSI S3.13.
3. System to measure:

Frequency

Rise time

Fall time

Duration

Over shoot

THD (Total Harmonic Distortion)
4. Piston phone or sound level meter calibrator.

Ear Simulator ANSI/ASA S3.7 or IEC 60318-1, Part 1: Electroacoustics - Simulators of human head
and ear - Part 1: Ear simulator for the measurement of supra-aural and circumaural earphones

Acoustic Coupler – NBS–9A (6cc) ANSI/ASA S3.7, or IEC 60318-3, Part 3: Electroacoustics –
Simulators of human head and ear – Part 3: Acoustic coupler for the calibration of supra-aural
earphones used in audiometry.

IEC 60318-5, Electroacoustics – Simulators of human head and ear – Part 5: 2 cm3 coupler for the
measurement of hearing aids and earphones coupled to the ear by means of ear inserts

IEC 60318-6, Electroacoustics – Simulators of human head and ear – Part 6: Mechanical coupler
for the measurement of bone vibrators
5. Specification / calibration information for all microphones, filters, SLM, and couplers showing correction
values needed to be applied to maintain accuracy.
6. Other couplers and adapters as stated or specified by manufacturer of the audiometer.
7. Calibration reports/sheets that demonstrate the audiometer meets the requirements and records the
measurement results of the calibration.
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