Week 7: Introduction to microphones

Microphone Design

Dynamic Microphones - Electromagnetic Inducer

These microphones function using a voice coil (a diaphragm + coil of wire) within the field of a permanent magnet. When the diaphragm moves the coil through the path of the magnet it creates electricity.
 * High SPL
 * Cheaper
 * Durability

Ribbon Microphone

Manufacturers: Coles, Royers, AEA,

These Microphones function with a very fine ribbon which osculates between magnet to produce electricity.

For Passive ribbon microphones you need need a high quality pre-amp to use the signal.

Active ribbon microphones have a pre-amp built into the microphone.

Condenser Microphone -

This has two plates, one functions as the diaphragm by moving back and forth. Each plate is charged - and + and the plates are charged via phantom power.

As the front plate moves based on the SPL the voltage changes by minute amounts. These voltages are sent to a pre-amp in the bottom of the microphone. The Pre-amp is also power by phantom power.
 * Good at capturing Transient Response
 * Good for high frequency signals (Overheads on drums, acoustic guitar)
 * Very easily broken

Electret Condenser

This is a normal condenser microphone with one exception. The plates have a permanent electronic charge so it doesn't have to relay on phantom power.

The CAD E-350 (Large diaphragm condenser) requires both phantom power and 2 9-volt batteries.

[Note: In the 1970's the Crown corparation designed aMic to fix "Comb filtering" caused by extreme phase cancellation from reflected sound. To fix this they created "Pressure Zone Microphone" (PZM). PZM is trademarked so other companies will call them boundary.]