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Microphones and Acoustics

Frequently Asked Questions

Get your most commonly asked acoustics questions answered.

Section I: Definitions and Terminology
Section II: Microphone Recommendations
Section III: Calibration and Testing
Section IV: Specification Clarifications
Section V: Specialty Microphone Applications
Section VI: Maintenance and Handling

If you don’t see the answer to your question, call our 24/7 SensorLineSM 716-684-0001 to speak with an application engineer or visit Ask the Acoustics Experts.

What is the maximum SPL limit of a microphone? How is it specified?

When the microphone experiences a change in pressure the output voltage of the preamplifier produces a waveform proportional to the amplitude and frequency of the sound.  At very high amplitudes mechanical and electrical characteristics of the system may become non-linear resulting in distortion of the waveform.  The maximum sound pressure level that a microphone can accurately detect is characterized by the total harmonic distortion (THD), expressed as a percentage. The dynamic range limit is defined as the peak sound pressure level required to produce 3% to THD in the output of the preamplifier.  The actual maximum SPL that can be measured is based upon the exact sensitivity level of the microphone and the peak voltage supplied by the preamplifier, the DC bias voltage in the preamp, and the excitation voltage of the signal conditioner. To maximize the upper limit of dynamic range, select a microphone with low sensitivity, high maximum peak voltage output, and use a signal conditioner with sufficient excitation voltage to allow for the full voltage swing (DC bias + peak output voltage).  

What is the maximum SPL limit of a microphone? How is it specified?

When the microphone experiences a change in pressure the output voltage of the preamplifier produces a waveform proportional to the amplitude and frequency of the sound.  At very high amplitudes mechanical and electrical characteristics of the system may become non-linear resulting in distortion of the waveform.  The maximum sound pressure level that a microphone can accurately detect is characterized by the total harmonic distortion (THD), expressed as a percentage. The dynamic range limit is defined as the peak sound pressure level required to produce 3% to THD in the output of the preamplifier.  The actual maximum SPL that can be measured is based upon the exact sensitivity level of the microphone and the peak voltage supplied by the preamplifier, the DC bias voltage in the preamp, and the excitation voltage of the signal conditioner. To maximize the upper limit of dynamic range, select a microphone with low sensitivity, high maximum peak voltage output, and use a signal conditioner with sufficient excitation voltage to allow for the full voltage swing (DC bias + peak output voltage).