Microphone

Introduction

A microphone is a device created by Emile Berliner in 1877 that serves as an input device. Its purpose is to convert sound waves into electric waves or input audio into computers. By converting sound waves into electrical signals, it captures audio, which can be in the form of digital or analog signals. This process can be carried out by computers or other digital audio devices. The initial electronic microphone was based on a liquid mechanism that utilized a diaphragm connected to a current charged needle submerged in diluted sulfuric acid solution. However, this mechanism was unable to effectively reproduce intelligible speech.

What exactly is a microphone?

Microphones are often designed with consideration for directionality and the type of device being used. For instance, omnidirectional microphones are capable of capturing all sounds within their range but may struggle when it comes to focusing on specific subjects amidst background noise. Bidirectional, directional and shotgun microphones are particularly useful for interviews and discussions. However, using two unidirectional microphones can achieve similar results, such as cardioid microphones.

How do computers utilize microphones?

Computers employ microphones for various purposes;

 They are used for voice recording.

 They provide users with the option of voice recognition.

 They enable users to record musical instrument sounds.

 They facilitate online chatting.

We can use it for VoIP (Voice over internet protocol). Additionally, it has applications in computer gaming. Moreover, it enables voice recording for singing, podcasts and dictation purposes.

How does a microphone function? 

When someone speaks, the sound waves are captured by the microphone, which converts them into energy. Inside the microphone, there is a diaphragm made of thin plastic that moves back and forth when it is hit by sound waves. This diaphragm is connected to a coil that also moves back and forth. The coil interacts with a magnetic field produced by a permanent magnet. As the coil moves through the magnetic field, it generates an electric current.

This electric current flows through the microphone and can be used for various purposes such as recording sounds or amplifying them through a loudspeaker, which transforms electrical signals into louder audio. It allows you to store and play back sounds indefinitely.

Type of Microphone

 There are different types of microphones available based on their specific uses.  Omnidirectional microphones : omnidirectional microphones that capture sounds from all directions but may struggle to isolate specific subjects in noisy environments. A commonly seen omnidirectional microphone is the lavalier mic often used in television production.

Directional microphones : Directional microphones, also known as unidirectional, excel at capturing sounds coming from a specific direction. They prove to be valuable in scenarios where there is considerable ambient noise present.

Shotgun microphones, a type of directional microphone commonly employed in film and television production, are designed to capture audio from a distance.

Bidirectional microphones : Bidirectional microphones, also known as two directional microphones, are specifically designed to capture sound from two different directions. This makes them particularly suitable for recording conversations and discussions.

For instance, dictation machines often utilize bidirectional microphones for their functionality.

Condenser microphones : Condenser microphones operate by utilizing the varying electrical charge of a capacitor. The diaphragm of the microphone acts as one of the capacitor’s plates. To bias the plate, a fixed charge is applied, typically derived from an amplifying battery.

The capacitance changes accordingly with the movement of the diaphragm in relation to other plates. This variation allows for recording sound in the form of an electrical signal.

For example, electret microphones are commonly found in cell phones and computers as a type of condenser microphone that employs a polarized ferroelectric material.

Laser microphones  : Laser microphones function by utilizing surface vibrations that occur due to sound waves. These vibrations cause lasers to return at different angles, which are then interpreted and transformed into sound waves.

Laser microphones find utility in situations where it is necessary to record sounds from a distance.

Ribbon microphones : Ribbon microphones are constructed using a slender strip of conductive metal that is suspended within a magnetic field. Aluminum, duralumin or nanofilm are often used materials for producing the ribbon itself.

When the microphone detects sound waves, the thin strip inside starts vibrating, resulting in the generation of an electrical signal.

Recording studios commonly utilize ribbon microphones to capture music because they have a reputation for producing a pleasant and authentic sound.

The history of microphones

The initial microphone design involved a liquid based system where a diaphragm was connected to a needle charged with current in a solution of diluted sulfuric acid. However, this early microphone was unable to reproduce speech clearly.

To achieve better results, the first functional diaphragm microphones utilized a metal sheet attached to a needle that recorded vibrations onto a foil medium.

When the needle moved across the foil during playback, the process was reversed, translating those vibrations back into audible sounds through the same metal diaphragm.

In 1878, David Edward Hughes invented the primitive carbon rod microphone, which played a crucial role in telephony’s development.

These devices relied on carbon’s variable electrical resistance when compressed between metal plates to convert airborne sound waves into an electrical signal.

Microphones today

Advancements in microphone technology have resulted in various types of microphones catering to different applications and needs.

Digital microphones have gained widespread popularity due to their enhanced sound quality and durability. Moreover, wireless microphones have become increasingly common across various settings such as live concerts and television production. Nevertheless, analog microphones still find extensive use given their availability and affordability.Microphones have become a crucial component of modern technology and will remain significant in the future.

Additional FAQ

1.What is a microphone in simple terms?

A microphone is a device that converts sound vibrations in the air into electronic signals and records them onto a recording medium or plays them through a loudspeaker. Microphones are used in various audio recording devices for communication, music vocals, speech and sound recording.

2.What does “microphone input” mean?

A microphone input refers to an input specifically designed to handle signals from microphones. It is typically characterized by low impedance and balanced connections using XLR connectors. In some cases, TRS connectors or 1/4 inch TS connectors with unbalanced operation and higher impedance may also be used.

3.Who was responsible for inventing the microphone?

The inventor of the microphone was Emile Berliner. His design became an integral part of the first Bell telephones and his gramophone was the first record player to use disks. Berliner was born in Hanover, Germany and studied at the Cooper Institute (now Cooper Union) while also assisting in a chemical laboratory.

4.What are headphones and microphones?

Both headphones and microphones serve as transducers as they convert one form of energy into another. A microphone converts acoustic energy into electrical energy, whereas a speaker (headphone) converts electrical energy into acoustic energy.

5.Who is considered the pioneer of microphones?

David Edward Hughes, a highly esteemed scientist from the era, was born on May 16th, 1831. He is renowned for being the creator of the carbon microphone, a significant contribution to the advancement of telephony.