- Anthony
Microphones are devices that translate sound waves into electrical signals. So, how a microphone works? They are essential to many electronic devices, including phones, radios, and computers. There are many different microphones, but microphone construction and working by converting sound waves into electrical signals.
What Is A Transducer?
What exactly is a transducer? A transducer is a device that microphone energy transformation one kind of energy into another.
Transducers, such as microphones transform mechanical wave energy into electrical energy. To put it another way, microphones transform sound waves into audio signals.
The Microphone As A Transducer
The diaphragm of a microphone responds to the sound waves it receives. The microphone generates a corresponding mic signal when the diaphragm moves in response to shifting sound pressure levels.
Let’s define the energies in the issue before delving into the mechanics of how a microphone transforms energy.
Mechanical Wave Energy (Sound Waves)
What exactly is mechanical wave energy? The energy carried by a mechanical wave is referred to as mechanical wave energy (an oscillation of matter within a medium). Mechanical waves (and hence mechanical wave energy) can only be transported via mediums with elasticity and inertia (gas, liquid, solid).
What exactly is a sound wave? A sound wave is a mechanical wave characterized by the pattern of particle disruption inside an elastic media [gas (typically air), liquid (often water), or solids]. The oscillations of particle disturbances generated by sound waves occur between 20 and 20,000 Hz.
The intensity of a sound wave is often measured in decibels (dB SPL) or Pascals (Pa).
The frequency range of audible sound waves is 20 Hz – 20,000 Hz. Infrared infrasound occurs below 20 Hz, whereas ultrasound occurs beyond 20,000 Hz.
When I say “inaudible,” I specifically mean inaudible to humans.
Electrical Energy (Audio Signals)
What exactly is electrical energy? Electric potential energy is what is meant by “electrical energy.” It is powered by electric current and potential (voltage) and provided through electrical circuitry. Electrical energy is captured in contemporary times and is almost always transformed into another sort of energy (heat, motion, light, etc.).
What exactly is an audio signal? An audio signal is a kind of electrical signal that expresses sound as electrical energy. AC voltages in millivolts (RMS) or decibels relative to voltage are used to measure analog audio signals (dBV or dBu).
Microphone Transducers
Microscopic devices transfer mechanical energy to electrical energy.
How they do so differs depending on the kind of microphone. This essay will go through how each [common] kind of microphone operates.
Microphone Transducer Types
Several microphones are available, each with its own set of characteristics. When it comes to the transducer, however, there are two major types of microphones:
- Transducers for dynamic microphones
- Transducers for condenser microphones
The Dynamic Microphone Transducer Type
When we say “dynamic microphone,” we usually mean a moving-coil dynamic microphone.
Moving-coil and ribbon microphones are both types of dynamic transducers.
What is the kind of dynamic microphone waves transducer? Dynamic microphones use electromagnetic induction to transform sound waves into audio signals. Moving-coil and ribbon microphones both contain conductive diaphragms that oscillate in the presence of persistent magnetic fields. A mic signal is produced when the diaphragm shifts in response to shifting sound pressure.
Conversion Of Energy In A Moving-Coil Dynamic Mic
The sound waves in the figure above strike the diaphragm of the Shure SM57 moving-coil dynamic microphone. The SM57 turns diaphragm movement into electrical energy, outputting as the mic signal.
The diaphragm moves in response to the pressure exerted by sound waves (mechanical energy). The diaphragm is connected to a conducting coil, and they move as one unit (hence the name moving-coil dynamic mic).
It should be noted that the diaphragm is not electrically conductive.
Magnets within the microphone’s cartridge (capsule) create a persistent magnetic field. The coil is inserted into a cylindrical groove inside the magnets such that it does not come into contact with the magnets yet is substantially influenced by the magnetic field.
Magnetic induction asserts that the magnetic flux changes when a conductive coil travels inside a permanent magnetic field. A changing magnetic flux produces a voltage across the conducting coil.
The conducting coil travels back and forth between equilibrium and sound waves as the diaphragm does. This causes a positive voltage to change one direction and a negative voltage to change the other. This produces an alternating current electrical signal across the coil.
This alternating current signal is often routed via a step-up transformer inside the microphone and outputted as the microphone audio signal.
Conversion Of Energy In A Ribbon Dynamic Mic
The sound waves in the figure above strike the diaphragm of the AEA R84 ribbon dynamic microphone. The R84 turns diaphragm movement into electrical energy, outputting as the mic signal.
The ribbon-like diaphragm (dynamic ribbon mic) moves in response to sound wave pressure (mechanical energy).
Ribbon diaphragms are formed of conductive material (typically corrugated metal) and are placed within a magnetic baffle that creates a persistent magnetic field.
Magnetic induction says that the magnetic flux changes while the conductive ribbon diaphragm moves inside a permanent magnetic field. A changing magnetic flux creates a voltage across the ribbon diaphragm.
An alternating current voltage is produced across the diaphragm as it travels back and forth about the sound waves.
This alternating current signal is often routed via a step-up transformer inside the microphone and outputted as the microphone audio signal.
How A Microphone Works?
The Basics
Microphones are a sort of transducer, a device that changes the shape of energy. Acoustic energy (sound waves) is converted into electrical energy by microphones (the audio signal).
Different microphones transfer energy in different ways, but they all have one thing in common: the diaphragm. This is a tiny piece of material (such as paper, plastic, or aluminum) that vibrates when sound waves strike it. The diaphragm is positioned in the head of a conventional hand-held microphone, such as the one shown below.
When the diaphragm vibrates, other components in the microphone vibrate as well. The vibrations are transformed into an electrical current, which is then translated into an auditory stream.
The loudspeaker, at the opposite end of the audio chain, is likewise a transducer, converting electrical energy back into acoustic energy.
Types of Microphone
There are many kinds of microphones in general usage. The distinctions may be classified into two categories:
1. The type of conversion technology they use
This is the technological technique through which the microphone converts sound into electricity. Dynamic condenser, ribbon, and crystal are the most popular technologies. Each has benefits and limitations and is best suited to certain applications. The pages that follow will go into further depth.
2. The type of application they are designed for
How microphones work? Some microphones are intended for broad usage and may be utilized well in various settings. Others are very specialized and solely serve their designated function. Aspects to consider include directional characteristics, frequency response, and impedance (more on these later).
Some relevant posts:
- What Is Gain On A Microphone? Top Full Guide 2023
- What Is A Lavalier Microphone? Top Full Guide
- What Is A Boom Microphone?
Mic Level & Line Level
A microphone generates a relatively little electrical current. This signal, known as mic level, is commonly measured in millivolts. Before it can be utilized for anything important, the signal must be amplified, often to line level (typically 0.5 -2V). Line level is the standard signal strength used by audio processing equipment and ordinary household equipment such as CD players, tape machines, VCRs, and so on because it is a more robust signal.
This is accomplished in one or more of the following ways:
- Some microphones have small built-in amplifiers that enhance the signal to a high mic or line level.
- The microphone may be routed via a modest boosting amplifier known as a line amp.
- Each channel of a sound mixer has a tiny amplifier. Attenuators can accept microphones of varying levels and bring them all to a consistent line level.
- The audio signal is sent through a power amplifier, a specialized amp that increases the signal enough to be routed to loudspeakers.
FAQ
How do microphones convert sound into electrical signals?
A tiny magnet oscillates within a coil connected to the diaphragm of the dynamic microphone. When a sound wave causes the microphone’s diaphragm to vibrate, the magnet’s and coil’s relative motion produces an electrical signal by magnetic induction.
How does a microphone get power?
Mics are often powered by the same wire that also transports their audio. Phantom power, DC biasing, T-power, Plug-in power, and USB power are examples of this. This is also true for external power supply devices, albeit these cables often feature extra power-carrying ports.
Do microphones need speakers?
Although microphones do not need loudspeakers or headphones to operate (and vice versa), these audio equipment are often used in conjunction.
What type of energy is in the microphone?
Microphones are a sort of transducer, a device that changes the shape of energy. Acoustic energy (sound waves) is converted into electrical energy by microphones (the audio signal).
Conclusion
Microphones are an important tool for many different applications. They can be used to record audio, communicate with others, and even amplify sound. There are many different types of microphones available on the market, each with its benefits. In this article, we will discuss the benefits of microphones in general.
