For microphone capsules, a higher signal-to-noise ratio (SNR) is generally better. However, some customers might assume that a capsule with a good SNR will also have better interference resistance.
In reality, SNR and interference resistance are not directly related. Therefore, a microphone capsule with a good SNR does not necessarily perform better in terms of interference resistance. Other factors must be considered as well.
Signal-to-Noise Ratio (SNR)
SNR is an important parameter for microphone capsules. It refers to the ratio between the maximum undistorted sound signal strength and the intensity of the noise emitted simultaneously. This ratio is commonly abbreviated as S/N and is expressed in decibels (dB).
In simple terms, a microphone with a higher SNR produces less inherent noise, while a lower SNR indicates higher noise levels.
For a microphone capsule, the SNR is largely determined by the capsule's internal SNR specifications. The SNR of the chip itself acts as the upper limit for the capsule's overall SNR. Additionally, poor packaging or inadequate filtering in the microphone capsule can degrade the SNR performance.
Interference Resistance of Microphone Capsules
The interference resistance of a microphone capsule refers to its ability to suppress external interference signals, and it is not directly related to the SNR. The performance of a microphone capsule in terms of interference resistance depends on several factors:
- The intrinsic interference resistance of the microphone chip itself. For example, the Korean 2324 chip offers strong resistance to Wi-Fi interference.
- The contribution of the capsule's filtering circuit to interference resistance. The filtering performance is primarily determined by LCR filters, where L usually refers to inductors or magnetic beads.
- The PCB board shielding effect. A double-sided copper PCB with large-area grounding is most effective.
- The shielding effect of the capsule's outer casing. The contact resistance should be less than 1Ω.
- The shielding effect of the leads. Using twisted pairs, shielded cables, and other similar techniques can improve interference resistance.
In summary, while SNR and interference resistance are both important characteristics, they are influenced by different factors and should be considered separately when selecting a microphone capsule.
