Microphone Principles and Design

Pressure transducers
Only the front face of a pressure transducer is exposed to the sound field. The diaphragm responds equally to all sound pressure fluctuations hitting the surface, doesn’t matter form which direction the sound. Pressure transducers have no directional characteristic, and are Omni directional.

Pressure gradient transducers
These microphones have a figure-8 pickup pattern along the longitudinal axis. They respond to the momentary sound pressure difference between two points A and B, which are a slight distance apart in the sound field.

Pick up Patterns

Omni directional
An Omni directional microphone, reveres to Omni because it hears from all direction. Provide the fullest sound from a distance. Omni is good to capture ambience and the room sound.

Pressure transducer

Bidirectional microphones only hearse from the front and the back and nothing from the sides.

Hears most of its sounds from the front and only a little from the back.

Transducer type

Magnetic Induction Transducer
Dynamic microphones work on the basis on magnetism. As the coil, that is mounted to the diagram moves in and out in relation to the SPL and cuts through the magnetic field. A current is induced in the coil, and that is a voltage representation of the sound.

Variable Capacitance Transducer
There are two plates placed close to each other, there is a potential difference on the plates. As the SPL hits the diaphragm the plates start to bind in relation to the sound. As the plates bend it causes electrons to jump, and you will get the voltage representation of the sound

Multi Pick up pattern

1. A microphone with multiple pickup patterns typically uses voltage difference between two condenser cardiod capsules. The different voltages on the plate causes different pick up patterns. Here are the different voltages on the different plates.
Omni = + +
Fig 8 = + –
Cardiod = + –
Cardiod = + +

2. A microphone with ports on their side provides an alternate way to put the sound from the back and the sound from the front out of phase. And change between Omni and cardiod. omnivoid inc

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