Calibration is defined as the process of measuring against a known standard. In terms of audiometry, the reason for calibration is to verify that the tones and decibels being presented to the client from the audiometer are within the required parameters, i.e. that when 1000 Hz is presented to the client that the correct number of wavelengths are in fact generated. Regular calibration is vital since an un-calibrated audiometer may present inaccurate tones and/or decibels. This possible inaccuracy of the un-calibrated audiometer may in turn cause the person being tested to have an audiogram recorded that does not accurately represent their hearing threshold at that time.