An Insider’s Perspective on Audiometer Calibration
Frequently Asked Questions about Audiometer Calibration
This blog was written by Mike Kawa, School Health Service Technician. Mike has 13 years of combined experience in the metrology and audiology industries. He spent 9 years running the repair department of a metrology lab and since 2007 has been servicing the customers of School Health in our Calibration, Parts, and Repair Department.
2 Compelling Reasons To Calibrate Your Audiometer Once a Year:
It is recommended by the manufacturer. Manufacturers recommend calibrating your audiometer once a year in order to get the best screening results.
It is mandated by your state. Most states mandate an audiometer be checked and calibrated once a year (check with your state school nurse consultant).
Why Do Manufacturers and States Require an Annual Calibration?
Manufacturers and state departments know that normal wear and tear on your audiometer can throw your audiometer’s settings out of specification without you knowing about it. They cannot guarantee your machine is within specifications after 1 year of use. Any screenings performed on a machine that is out of specification are not valid.
What Causes an Audiometer’s Settings to Get Out of Specification?
Unfortunately, normal use of an audiometer also causes specifications to deviate from the national standard. For instance, if you move your audiometer from place to place or simply use the headphones provided with the unit, this can cause the settings to change or pieces (such as the headphone cord) to degrade over time.
What Happens When I Send in my Audiometer to Be Calibrated?
During a calibration, a service technician compares your audiometer to special calibration equipment that is of a greater standard. For instance, at School Health, we have a service department that calibrates audiometers. We know our equipment is of greater standard because we make sure our equipment has “traceability” – which is an unbroken chain of measured comparisons to a recognized national standard. Basically, this means that hearing screening done on the East Coast is to the same standard of screening done on the West Coast because we go through the proper channels to ensure our calibration equipment meets the national standards.
We check all of the functions of an audiometer during a calibration, but one of the most important functions we check is the Sound Pressure Levels. This is the measurement of the output level for each frequency. This is usually recorded as a deviation from the standard expected in the form of +/-.
Calibration Check vs. Calibration
Technically speaking, the term “calibration” means comparing your specifications to a known standard. What it doesn’t mean is adjusting the settings to be within specifications. You may hear terms such as “exhaustive calibration” or “calibration with adjustment” that includes making the proper adjustments to your machine to meet national specifications.
At School Health we try to clear up the issue by offering two types of testing. One choice is a Calibration Check. This is the comparison to the known standard without any adjustments. The outputs levels are checked and if everything is within specification the measurements are recorded and the unit is returned to the end user. If the settings are not within specification, then you can ask us to move ahead with a Calibration.
When a customer orders a Calibration from School Health, all the adjustable output levels are corrected to national standards as close as possible and then recorded.
Whatever Calibration is selected an annual analysis of an audiometer is most important.
Send in your audiometer to School Health to be checked or calibrated >>