- The mic was invented by multiple inventors working independently.1
- Thomas Edison found in 1878 that carbon connected to a circuit would change resistance when vibrated by sound waves.1
- Most notably, Alexander Graham Bell use a magnet and a diaphragm that was sensitive to sound waves and would vibrate.1
- The magnet created a current in a coil via induction.1
- All these innovations were intended for telephone, not amplification.1
- The inventions of what is called a condenser microphone and the vacuum tube made effective radio broadcasting and the amplification of public performances possible.2
- In 1929 and 1930 NBC used parabolic dishes with their microphones to create directional recording techniques.2
- “Paved the way for shotgun mics”2
How it Works
- Dynamic mics use a magnet with a wire coiled around it. When a diaphragm is vibrated with sound waves, it moves the coil along the magnet creating a current in the coil wires as an audio signal.3
- Described as cold sounding, but very durable and not as sensitive as other mics.
- Condenser microphones use two plates. The plate that faces the sound waves acts as a diaphragm.4
- The system is loaded with 48V of what is called phantom power.4
- When the diaphragm vibrates the modulation between the plates sends the audio signal in the form of the signal modulation down the wires connecting the plates.4
- Ribbon microphones are highly sensitive mics that use a similar tech as dynamic mics.5
- In the case of a ribbon mic there is a thin ribbon that both acts as a diaphragm and is also a part of the circuit, such as the coiled wire in a standard dynamic mic. The magnet is in the shape of a U and the ribbon modulates between the U shape to create the audio signal.5
- They are extremely sensitive (storing on the side, wind, or any kind of voltage spike can break them.5
- Most mobile phones and small electronics have traditionally used an electret microphone which is a “condensed” condenser microphone.6
- The new kid on the block is the MEMS microphone.
- MEMS mics use the same principle as the electret condenser mic but on a much smaller scale.7
- Used for smaller electronic applications.
- Company called ReSpeak makes a Raspberry Pi unit with four speakers so that people can mess with voice applications such as the Amazon Echo.7
- Noise Canceling applications.
- Internet of Things.
- Wireless and smaller mics/earbuds.
- As wearable tech becomes more useful, better mics will become important, as well as the software that can filter the signals and improve voice recognition and clarity.