In day-to-day acoustic measurements, it’s common to hear: “Insert the measurement microphone into the calibrator, press the button, and the microphone is calibrated.” From an engineering and metrology perspective, that wording is an oversimplification. To place a sound calibrator correctly in the measurement chain, we should start with what it generates—and what it can (and cannot) verify. 

Core Function of a Calibrator

A sound calibrator is essentially a reference sound source that generates a stable, known sound pressure level (SPL) at a specified frequency—typically 1 kHz (and 250 Hz on some models). Depending on the model, the nominal level is often 94 dB or 114 dB.

During use, you compare the calibrator’s nominal SPL with the reading of the entire measurement chain (microphone + preamplifier + front-end or sound level meter) to confirm whether the indicated value matches the reference.

In other words, a calibrator is primarily an on-site verification tool rather than a device that “calibrates” (adjusts) the microphone itself. It helps you answer one practical question: for a known SPL at a known frequency, is the system reading correct?

Relationship Between the Calibrator and the Measurement Microphone

Structurally, a calibrator mainly provides a controlled acoustic field at the microphone diaphragm. It does not change the microphone’s intrinsic characteristics—such as sensitivity, frequency response, linearity, dynamic range, or self-noise.

If the microphone or preamplifier drifts due to aging, mishandling, temperature/humidity exposure, or mechanical shock, the calibrator can reveal the deviation—for example, a consistent offset from the nominal level.

But the calibrator cannot “fix” the microphone. If the deviation is abnormal, unstable, or growing over time, you typically troubleshoot the chain (fit/seal, adaptor size, connector, cable, preamp gain, settings) and, when necessary, send the microphone and/or calibrator to a laboratory for calibration or service.

Understanding “Calibration” from a Metrological Perspective

In acoustic metrology, “calibration” generally means comparing a device to a higher-level reference standard and documenting its deviation (and, where applicable, a correction factor) with traceability to national or international standards.

For measurement microphones, a rigorous calibration is typically performed in a controlled laboratory environment, using reference microphones and equipment that comply with relevant standards (e.g., IEC 60942 for sound calibrators and the IEC 61094 series for measurement microphones). It commonly includes multi-point testing across conditions and an uncertainty statement.

In the traceability chain, a handheld sound calibrator is mainly an on-site step used to: 1) perform quick checks before and after measurements, 2) record drift during use, and 3) support decisions on recalibration or service.

Therefore, it’s more accurate to say: you are using a calibrator to verify the measurement system on-site—not completing a formal microphone calibration.

Also note: the calibrator itself is part of your traceability chain. To keep the check meaningful, ensure the calibrator has a valid calibration certificate and is used within its specified environmental range.

Summary

A calibrator is a very important on-site comparison tool in the measurement chain. It can:

• Provide a standard sound pressure level signal for measurement microphones
• Help engineers quickly check whether the measurement system is operating in a reasonable state

At the same time, it must be clearly understood that:

• The calibrator does not directly “calibrate” or repair the microphone itself
• Formal microphone calibration must be performed in a standard acoustic laboratory and must follow metrological specifications and procedures

In engineering practice, only by clearly distinguishing between “on-site verification” and “laboratory calibration” can we both efficiently carry out daily testing and ensure that measurement data are accurate and metrologically traceable.

You are welcome to visit www.crysound.com to learn more about microphone functions and hardware solutions, or contact the CRYSOUND team of  demonstrations and application support.