Electret Condenser Microphone
Electret Condenser Microphone, as the name suggests is a parallel plate capacitor and works on the principle of a variable capacitance. It consists of two plates, one fixed (called the back plate) and the other moveable (called Diaphragm) with a small gap between them. An electric potential charges the plate. When sound strikes the diaphragm it starts moving, thereby changing the capacitance between the plates which in turn results in a variable electric current to flow.
Advantages of Electret Condenser Microphone
They produce very accurate audio with wide
frequency response and low self-noise
As we mentioned, electret condenser microphones use
ultra-thin films as diaphragms, which are lighter and
more responsive to sound pressure. As a result, they
represent sound sources more accurately, with lower
self-noise, wider frequency response, and better
transient response (which means fast attack sounds
like percussion and plucked strings will be picked up
more accurately) .
They require less gain to achieve good recording
levels
Because electret condenser microphones have internal
preamp circuitry, they have a stronger output than
dynamic microphones, which means they require less
audio interface or mixer gain to achieve good
recording levels.
They are more sensitive and ideal for recording
over long distances
Another benefit of their design is that electret
condenser microphones are more forgiving than dynamic
microphones when it comes to the distance between the
microphone and the sound source. Electret condenser
microphones pick up sound more consistently and
farther than dynamic microphones, resulting in a more
balanced recording.
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Types of Electret Condenser Microphone
Foil Electret condenser microphone
Foil Electret condenser microphone were among the first types
developed. In these microphones, the electret material is a
thin foil that is placed directly behind the diaphragm. This
design is straightforward but can sometimes be limited in
terms of sound quality and long-term stability of the electret
charge.
Back Electret condenser microphone
In back Electret condenser microphone, the electret material
is not placed on the diaphragm but on the backplate of the
microphone capsule. This design offers several advantages,
including improved stability and consistency of the electret
charge over time, and greater flexibility in diaphragm
materials and construction. This type is widely used in modern
applications due to its robustness and reliability.
Other variations and their characteristics
There are also specialized Electret condenser microphone
designed for specific applications, such as noise-canceling
microphones, which use dual diaphragms to reduce background
noise, and miniature microphones for use in mobile devices,
where space is at a premium. These variations demonstrate the
versatility of electret microphone technology.
Shotgun microphones
Shotgun microphones are a type of condenser mic distinguished
by their long, tubular design. The purpose of a shotgun
microphone is generally to record audio from a distance while
maintaining focus and clarity.
USB condenser microphones
The major point of difference for a USB microphone is the way
the signal is output. Rather than an analog xlr connection,
USB mics such as the nt-USB mini feature a USB output and
on-board a/d (analog-to-digital) converters for turning the
electrical current produced by the capsule into a digital
signal that can be sent directly to a computer or other
digital recording device.
Application of Electret Condenser Microphone
Use in consumer electronics
Electret condenser microphone are a staple in consumer electronics
due to their compact size, high sensitivity, and affordability.
they are commonly found in smartphones, laptops, and tablets for
voice communication and audio recording. their small footprint
makes them ideal for integration into the limited space of these
devices.
Professional audio and recording
In the professional audio realm, Electret condenser microphone are
valued for their sound quality and versatility. they are used in
studio recording, live sound reinforcement, and broadcast
applications. their wide frequency response and high sensitivity
make them suitable for capturing a range of sounds, from spoken
word to musical performances.
Specialty applications
The flexibility of electret microphone technology allows for its
use in specialized fields. for instance, in surveillance, highly
directional Electret condenser microphone are used for focused
audio capture. in medical devices, miniature Electret condenser
microphone are employed in hearing aids and diagnostic equipment,
benefiting from their small size and reliability.
Field recording
Small diaphragm condenser mics are commonly used in field
recording to capture ambient sounds, nature sounds, or on-location
audio for film and video production.
Podcasting and broadcasting
Usb condenser microphones offer a convenient solution for
podcasters and broadcasters, providing plug-and-play functionality
without the need for additional equipment.
Live performances
While not as common as dynamic microphones for live sound,
condenser mics are sometimes used for live performances,
especially when a more detailed sound capture is desired, such as
with choirs or orchestras.
Studio production
In professional studio environments, large diaphragm condenser
mics are favored for their ability to capture a wide frequency
response and subtle sonic details, making them a go-to choice for
many producers and sound engineers.
Components of Electret Condenser Microphone
Top view
Removing the metal body reveals a cylindrical plastic covering
that provides mechanical strength and supports the entire
assembly. The entire assembly is called a capsule.
Capacitor plate
The two plates of the capacitor are the heart of the condenser
microphone, and the diaphragm (metal body) is a very thin
conductive metal film. It is deformable and elastic in nature. The
diaphragm is glued to a solid hollow ring, which provides the
necessary support for the diaphragm. The back panel is a thick
solid perforated metal plate. It is coated with permanently
charged electret material and requires no polarizing power source.
These electrets are made by melting a dielectric material
containing polar molecules (such as wax, plastic, etc.) and
solidifying it in a strong electrostatic field. The polar
molecules of the dielectric material tend to be in the direction
of the electrostatic field and create a permanent electrostatic
bias in it. In modern microphones, ptfe (polytetrafluoroethylene)
plastic is used to form the electrical material.
Diaphragm & spacer
The solid hollow ring of the diaphragm is used to connect the
diaphragm with the outer metal covering. A very thin plastic
spacer is placed between both the plates to insulate them as well
as provide the gap to move the diaphragm
Electrical connection &JFET
The diaphragm is electrically connected to one of the legs of the
microphone via the outermost metallic covering. A JFET (junction
field effect transitor) transistor is used to amplify the
electrical current generated. The back plate, fixed in the
capsule, is connected with the gate of the transistor, source is
connected with the ground of the external circuit and electrical
signal appears on the drain.
Electret Condenser Microphone:Technical Specifications and Performance
Frequency response
The frequency response of a microphone defines how well it can reproduce audio within the spectrum of human hearing (typically 20 hz to 20 khz). Electret condenser microphone often have a wide frequency response, making them suitable for a range of audio applications, from voice recording to high-fidelity music capture.
01
Sensitivity
Sensitivity refers to how effectively a microphone converts sound into an electrical signal. Electret condenser microphone are known for their high sensitivity, which means they can pick up fine audio details, making them ideal for studio recording and delicate sound reproduction.
02
Signal-to-noise ratio
The signal-to-noise ratio (snr) is a critical measure of a microphone’s ability to capture desired sounds while rejecting unwanted background noise. Electret condenser microphone generally have a good snr, ensuring clear audio capture even in environments with some ambient noise.
03
Directional characteristics
Electret condenser microphone can be designed with various directional patterns, such as omnidirectional, bidirectional, and unidirectional (cardioid). This allows for flexibility in how they pick up sound, whether capturing audio from all directions or focusing on a single source.
04
Main Differences Between Electret Condenser Microphone and Condenser Microphone
Polarization
A condenser microphone requires an external power source,
usually known as phantom power, to polarize the diaphragm and
backplate to create a capacitor. In contrast, an electret
microphone has a permanent charge due to a material called
electret, eliminating the need for an external power source to
maintain polarization.
Power requirement
As mentioned, condenser microphones typically need external
power, either through batteries or phantom power supplied by an
audio interface or mixer. Electret condenser microphone, on the
other hand, do not require external power since the electret
material provides a permanent charge.
Sensitivity
Electret condenser microphone are generally less sensitive
compared to condenser microphones. Condenser microphones tend to
have a wider frequency response and higher sensitivity, making
them suitable for capturing subtle sounds and nuances.
Cost and size
Electret condenser microphone are usually more cost-effective
and compact compared to traditional condenser microphones. This
makes Electret condenser microphone popular in applications
where size and cost are crucial factors.
Durability
Due to the permanent charge provided by the electret material,
Electret condenser microphone are often more durable and less
prone to degradation over time compared to condenser
microphones.
How to Maintain Electret Condenser Microphone
Handling with care
As sensitive instruments, these microphones should be handled with care to avoid damaging the delicate diaphragm.
Avoiding moisture
Humidity and moisture can potentially degrade the electret material over time. Hence, storing them in a dry place is advisable.
Regular cleaning
Like any piece of audio equipment, these microphones can benefit from regular cleaning to prevent dust accumulation.
Components of Electret Condenser Microphone
Electret capsule
The electret capsule is the heart of the microphone. It
consists of a thin diaphragm and a backplate with a
conductive material coating. The diaphragm vibrates when
sound waves hit it, and the backplate captures the
movement of the diaphragm. The electret capsule generates
an electrical signal that is proportional to the sound
waves.
FET amplifier
Electret condenser microphone have a built-in FET
amplifier that requires power to operate. The FET
(field-effect transistor) amplifier amplifies the
electrical signal generated by the electret capsule. It
also provides impedance matching and converts the high
impedance of the electret capsule to a low impedance
output.
Bias resistor
The bias resistor is a component that provides a dc
voltage to the FET amplifier. The voltage bias is
necessary to keep the FET amplifier in its active region
and prevent distortion. The bias resistor also helps to
stabilize the dc operating point of the FET amplifier.
Output capacitor
The output capacitor is a component that blocks dc voltage
and allows only the ac signal to pass through. It is
necessary to prevent any dc offset from the FET amplifier
from reaching the output. The output capacitor also helps
to remove any noise or interference from the dc power
supply.
An electret condenser microphone is essentially a highly specialized capacitor. For those who don't have an electronics degree, a capacitor is a passive electrical component designed to temporarily store energy in an electric field. Capacitors work by using two plates that are close to each other. The closer they are, the higher the capacitance, that is, the greater their ability to store charge. In electret condenser microphones, one of the plates is made of a very light, often very thin material, and acts as a diaphragm. For example, the diaphragms in the Presonus PX-1 and PM-2 microphones are made of gold sputtered mylar and are only 6 microns (0.006 mm) thick. When sonic hit, the diaphragm vibrates, changing the distance between the two plates, thus changing the capacitance. The resulting capacitance fluctuations produce an electrical representation of the input source's sound energy. Active circuitry is required to convert the very high impedance of the DC polarized capsule output into a usable low impedance; A +48V phantom supply is typically used to supply current to this circuit. Other methods include dedicated power supplies (typically used with tubular capacitors) and batteries (typically with electret capacitors).
Precautions for Using a Electret Condenser Microphone
Wear protective gear
Always wear protective gear such as gloves and saFETy glasses to
prevent any accident or injury while handling the microphone.
Use a power supply with caution
When using a power supply, ensure that it is designed for the
specific microphone you are testing. Incorrect voltage or polarity
can damage the microphone or cause a short circuit.
Avoid overloading the microphone
Overloading the microphone with high sound pressure levels can
damage the microphone or cause distortion in the audio signal.
Always start with low sound levels and gradually increase the
volume to avoid any damage.
Handle the microphone with care
Electret condenser microphone are delicate instruments, and
mishandling them can cause damage to the microphone or affect the
accuracy of the test results. Always handle the microphone with
care and avoid dropping or applying excessive force.
Disconnect the power supply when not in use
To prevent any accidents or damage to the microphone, always
disconnect the power supply when the microphone is not in use.
What Are the Trends and Development Directions of Electret Condenser Microphone in the Market
Recent advancements
Recent advancements in electret microphone technology focus on enhancing sound quality, durability, and miniaturization. Innovations include improved materials for the electret and diaphragm, as well as advanced manufacturing techniques that enhance performance and reliability.
Emerging applications
The evolving landscape of technology is opening new applications for Electret condenser microphone. For example, in smart home devices, Electret condenser microphone are used for voice command recognition, and in virtual reality, they enable immersive audio experiences. Additionally, developments in noise-canceling technology in Electret condenser microphone are enhancing their use in noisy environments.
Company Profile
Shenzhen Marquess Electronics Co., Ltd. was founded in July 2004, originating from the Japanese AOI Electric Motor Manufacturing Company as a joint venture specializing in the production of ECM (Electret Condenser Microphones).
Our Certificate
ISO 9001 2015,ISO 14001 2015,ISO 4500 12018,UL E473299,UL E473487
FAQ
Q: What is an Electret Condenser Microphone (ECM)?
Q: How does an Electret Condenser Microphone work?
Q: Are Electret Condenser Microphones suitable for professional audio recording?
Q: Do Electret Condenser Microphones require phantom power?
Q: Can Electret Condenser Microphones be used with smartphones and computers?
Q: What is the frequency response range of Electret Condenser Microphones?
Q: How do Electret Condenser Microphones compare to Dynamic Microphones?
Q: Can Electret Condenser Microphones be used for outdoor recording?
Q: Do Electret Condenser Microphones require regular maintenance
Q: Are Electret Condenser Microphones suitable for vocal recording?
Q: Can Electret Condenser Microphones be used for instrument recording?
Q: What is the polar pattern of most Electret Condenser Microphones?
Q: Do Electret Condenser Microphones require a pop filter for vocal recording?
Q: Can Electret Condenser Microphones be used for podcasting and streaming?
Q: Are Electret Condenser Microphones suitable for field recording?
Q: What is the typical impedance of Electret Condenser Microphones?
Q: Can Electret Condenser Microphones be used for ASMR recording?
Q: Do Electret Condenser Microphones come with accessories like shock mounts and windshields?
Q: What is the lifespan of an Electret Condenser Microphone?
Q: What is the purpose of condenser microphone?