Microphone

Microphones for Computers

This text addresses matching microphones to computers and requirements. Solutions described here are oriented to users and constrained to solutions that work with GNU compatible kernels.

First characteristics of the components are described, then combinations of components for use.

Computer inputs

Analog inputs and outputs on computers use Tip, Ring, and Sleeve (TRS) type connectors. The microphone connector is a TS connector, headphones are TRS.

Microphone input

A microphone connected to this input socket is routed to an internal preamplifier then analog to digital converter (ADC). The connector socket is marked with pink.

Line input

Connects to ADC. The connector socket is marked with light blue.

Converting audio to electrical signals

Common microphones convert audio into electrical signal in 1 of 2 ways: dynamic or condenser.

Dynamic

do not need power.

Condenser

Some condenser microphones use electrets and are called “electret microphones“.

needs power and can be powered by

• battery
• the cable which also carries the audio signal. This is called 'phantom power'. The power is 48V or 12V for low impedance and 3V to 5V for high impedance.

Connection or wiring schemes and electrical characteristics

There are 2 sets of schemes which we will refer to by impedance. The impedance has otherwise no significance to the consumer.

Low impedance

Connectors are XLR.

Electrically balanced. Two signal wires are the inverse of each other relative to a ground connection.

High impedance

Connectors are ¼ inch TS plugs which have 2 electrical connections on the plug.

Electrically unbalanced. 1 connection is the Tip, the other is the Sleeve.

Mixing Impedances

impedance transformer example.