6.11: Mic Limitations

Mic Limitations (Distortion)

Microphones have limits and can become distorted when exposed to very loud sound sources that exceed their maximum sound pressure level (SPL). This distortion can result in harshness, clipping, or an inaccurate representation of the sound.

Pad Switch

To manage this, many microphones (particularly condenser mics) include a built-in pad switch. A pad reduces the microphone’s output level by a fixed amount, such as –10 dB or –20 dB, before it reaches the preamp. By lowering the output signal, the pad prevents overloading either the microphone’s internal electronics or the connected equipment.

• The pad switch may be built directly into the microphone’s body.
• Alternatively, a pad switch/button may be located on a mixing console or a mic preamp.

The more sensitive a microphone is, the louder its output will be, which increases the risk of overload when capturing loud sources like drums, brass instruments, or amplified guitars.

Signal-to-Noise Ratio (S/N)

Microphones also have a signal-to-noise ratio (S/N) rating. This measurement compares the strength of the desired audio signal to the level of background noise inherent in the microphone’s circuitry. The signal-to-noise ratio is always expressed in decibels. The higher the decibel the better the ratio.

• A higher S/N ratio means the microphone delivers a clearer signal with less self-noise.
• A lower S/N ratio indicates that the microphone’s internal noise may be more noticeable, especially in quiet recordings.

The S/N ratio is critical in professional recording, as it determines how clean and transparent the microphone will sound, particularly in high-fidelity environments.