Functional check
Before each day’s use: listen to the audiometer and test it on a person with known, stable hearing, checking for distortion, unwanted sound and attenuator problems.
Calibration certificates
Audiometer calibration certificates
A calibration certificate is the record that an audiometer was checked against its standard, and the document inspectors, auditors and customers ask to see. Here is what a good one contains, and how the ACS produces it.
The ACS certificate
Every result, on one certificate.
When a calibration is finished, the ACS prints a certificate that is ready to hand to the customer.
- A condensed listing of every test result
- Audiometer and transducer serial numbers
- The microphone, mastoid and coupler used for the measurements
- The calibration standards the audiometer was tested against
- Out of spec values highlighted in red
- Color graphs of the results
- Your company logo in the upper right corner
Checklist
What an audiometer calibration certificate should show
Whoever performs the calibration, these are the details that make a certificate useful when it is reviewed later.
| The instrument | Make, model and serial number of the audiometer, and of each headphone, insert earphone and bone oscillator that was calibrated. Transducers are calibrated as a pair with the audiometer, so swapping one means recalibrating. |
|---|---|
| The standard | Which standard the audiometer was checked against and which edition, for example ANSI S3.6 or IEC 60645, with ISO 389 reference levels. What these standards cover. |
| The results | Measured values for each frequency and transducer next to the target and the tolerance, so a reviewer can see how close each one was, not just pass or fail. |
| Before and after adjustment | If the audiometer was adjusted, the values found before adjustment show how far it had drifted since the last calibration. The ACS records these “pre-adjustment” values with every calibration. |
| The measuring equipment | The microphone, coupler and artificial mastoid used, so the measurement can be traced back to calibrated equipment. |
| Who and when | The date of the calibration and who performed it, so the next calibration can be scheduled on time. |
Schedule
How often does an audiometer need calibrating?
For audiometers used in occupational hearing conservation programs in the United States, OSHA’s noise standard (29 CFR 1910.95, Appendix E) sets three levels of check. Clinics outside OSHA programs commonly follow the audiometer manufacturer’s recommendation, which is usually a yearly calibration.
Acoustic calibration
At least once a year, or whenever the functional check finds a problem: measure the output levels with a sound level meter, microphone and coupler.
Exhaustive calibration
At least every two years: a full check of output levels, frequency, distortion, linearity, rise and fall time and the rest of the specification.
In-house calibration
Producing certificates yourself
Audiometer manufacturers, distributors, service companies and hospital biomedical departments use the ACS to calibrate audiometers and print certificates in house. With automatic control, the ACS steps through every test point and adjusts the audiometer itself; an exhaustive calibration takes under 10 minutes on most models.
The ACS has built-in setups for 125 instrument models, and stores every calibration so you can page back through earlier results for the same audiometer and headphones.
See the ACSReady to speed up your calibrations?
Get pricing for your configuration, or see the ACS in action.