Many customers often have misconceptions about microphone capsule sensitivity. This article aims to clarify these misunderstandings and provide a clear explanation.
What is Microphone Capsule Sensitivity?
A microphone capsule, specifically an electret condenser microphone (ECM), converts sound energy into electrical signals. It is widely used in digital audio devices, surveillance, cameras, and microphones.
However, some buyers of microphone components may confuse the concept of sensitivity. Let's clarify how microphone sensitivity is measured and interpreted.
Understanding Microphone Sensitivity Ratings
Microphone sensitivity is usually expressed in negative decibels (dB). The key principle to remember is:
- A smaller (less negative) dB value means higher sensitivity.
- For example, -30dB is more sensitive than -40dB.
- This is because the standard reference is 0dB = 1V, so -30dB is closer to 0 than -40dB, indicating greater sensitivity.
Ways to Measure Microphone Sensitivity
1. dBV per Microbar
Measured with an open circuit microphone under a sound pressure level of 74 dB SPL (Decibel Sound Pressure Level). The reference voltage is 1V.
2. mV / Pa
Measured at 94 dB SPL, indicating the millivolt output of the microphone.
3. dBm / 10 Dynes / cm²
Measured at 94 dB SPL, with the microphone matched to a specific impedance. The dB value is referenced against 1 milliwatt.
4. dBm, EIA Rating
Measured at 0 dB SPL with a specific impedance match. The dB value is also referenced against 1 milliwatt.
Does Higher Sensitivity Mean Better Audio Quality?
Not necessarily. While a higher sensitivity means better sound pickup, it can also increase background noise. Choosing the right sensitivity depends on the application and environmental conditions.
Sensitivity is a key factor in microphone performance, but it should be considered alongside other parameters like signal-to-noise ratio and distortion. For professional applications, additional testing is required to assess audio quality.
