The Complete Guide To Moving-Coil Dynamic Microphones
If you've ever been to a live band performance or have hung out in a recording studio, chances are you've seen plenty of dynamic microphones. Moving-coil dynamic microphones are commonly used in music recording, broadcasting, podcasting, and live venues around the world.
What is a moving-coil dynamic microphone? A moving-coil dynamic microphone converts sound to audio via electromagnetic induction. It does so with a cartridge/element with a conductive coil attached to a movable diaphragm that vibrates within a magnetic structure. The diaphragm movement causes a coinciding audio signal to be produced.
This article is the complete guide to moving-coil dynamic microphones. Its purpose is to answer all your questions on moving-coil dynamic mics as a whole and will feature some microphone examples to further our understanding.
Table Of Contents
- What Is A Moving-Coil Dynamic Microphone?
- A Bit Of History On Moving-Coil Dynamic Microphones
- How Do Moving-Coil Dynamic Microphones Work?
- Electromagnetic Induction
- General Characteristics Of A Moving-Coil Dynamic Microphone
- Applications Of Moving-Coil Dynamic Microphones
- Moving-Coil Dynamic Microphone Examples
- Differences Between Dynamic And Condenser Microphones
- Related Questions
What Is A Moving-Coil Dynamic Microphone?
Let's start by stating that the term “dynamic microphone” nearly always refers to the moving-coil dynamic microphone even though, technically speaking, ribbon microphones are also dynamic. So moving-coil mics are better known simply as dynamic mics, and ribbon mics are known as ribbon mics (rather than “dynamic ribbon mics”).
The most basic definition of a moving-coil dynamic microphone is as follows:
A microphone that has a conductive coil (typically copper) attached to a moveable diaphragm (typically Mylar) that moves within a permanent magnetic field supplied by a magnetic structure.
Dynamic microphones work as transducers on the principle of electromagnetic induction. This principle essentially states that as an electrically conductive material (i.e., the moving-coil) moves within a permanent magnetic field, a voltage is induced across the conductor. So as the diaphragm (and coil) moves, the dynamic mic creates an audio signal.
This explains the working principle and defining factor of dynamic microphones. Of course, there's more to it than that, and we will dive deeper into each design component and the principle of electromagnetic induction in this article.
A Bit Of History On Moving-Coil Dynamic Microphones
The history of the moving-coil dynamic microphone begins with the invention of Ernst Werner von Siemens, the German electrical engineer and inventor. He was awarded a German patent for his moving-coil microphone in 1877. Some say he had initially invented the microphone as early as 1874.
This first step into dynamic microphones was designed with a flexible diaphragm and an attached conductive coil. This diaphragm/coil component was designed to move within a magnetic structure, and as it did so, a small electrical current (audio signal) was induced across the coil.
Though a major breakthrough in microphone technology, Siemens' moving-coil mic did not catch on at its time, magnets were not strong enough at the time to yield overly accurate results, and the transformer was yet to be invented, which played a significant role in producing usable dynamic mics in the early days.
Note that the transformer was invented in 1886, and magnets became strong enough for practical dynamic mics in the 1930s.
In 1923, English engineer Captain Henry Joseph Round produced the first-ever functional moving-coil-type microphone. This mic was named the Marconi-Sykes magnetophone since Captain Round was working as the chief engineer at Marconi at the time.
The magnetophone was made of a cylindrical iron pot with a carefully place cylindrical pole piece in its centre. In the gap between the outer pot and the inner pole piece, there was a conductive coil. One magnetic pole was to the interior of the coil, and the other magnetic pole was to the exterior.
At the top of this magnetic piece was a paper diaphragm. The diaphragm was attached at its outer circumference to the iron pot and was connected to the pole piece in the centre, giving it an annular shape. The diaphragm was also connected to a light conductive coil of aluminum wire via cotton-wool pads fixed with rubber solution.
As the diaphragm and coil moved back and forth within the magnetic field, an AC voltage was produced. This AC voltage would be the mic signal.
The mic signal was then sent through two amplifier stages (each made of an input transformer, multiple vacuum tubes, capacitors, resistors, and an output transformer). The signal was then sent through a final output transformer and outputted as a relatively strong audio signal.
This made for a relatively massive microphone, but it could produce fairly strong and clean audio.
In 1931, American scientists Edward C. Wente and Albert L. Thuras invented a close approximation of the modern moving-coil dynamic microphone. Improvements in material and design have happened since then, but the basic design has remained the same. This mic was known as the Western Electric 618A Electrodynamic Transmitter.
In 1959, Ernie Seeler of the Shure Brothers microphone company finished designing the first unidirectional top-address moving-coil dynamic microphone. Shure released this mic, known as the Model 545, in the same year. This was the first introduction of Shure's legendary Unidyne III moving-coil cartridge and marked a huge step forward for moving-coil microphones.
Shure
Shure is featured in My New Microphone's Top 11 Best Microphone Brands You Should Know And Use.
Since then, microphone manufacturers worldwide have continued to improve the design and performance of moving-coil dynamic microphones. These mics all come from the same history, which is worth knowing about when studying this popular mic type.
For an in-depth article on microphone history, check out My New Microphone's Mic History: Who Invented Each Type Of Microphone And When?
How Do Moving-Coil Dynamic Microphones Work?
It wouldn't be a complete guide if we didn't go into detail about how a moving-coil dynamic microphone functions. This is perhaps the most important section of this article.
To understand how dynamic mics work, we must understand their transducer elements. These elements are typically referred to as cartridges but can also be called capsules.
The Moving-Coil Dynamic Cartridge
Let's start by looking at a popular dynamic mic cartridge: the Shure R59 replacement cartridge for the famous Shure SM58 dynamic microphone.
So what's inside this capsule? Let's have a look at a simplified diagram to see the individual internal components:
So the basic dynamic cartridge is made up of a physical housing and the following 4 components:
Let's discuss each of these individual components in more detail:
Diaphragm
The diaphragm of a dynamic microphone is a flexible/moveable membrane that reacts to varying sound pressure (sound waves).
Many modern moving-coil microphones utilize Mylar as their diaphragm material. Mylar is a polyester film with high tensile strength and electrical insulation. It can be stretched thin in order to react accurately to sound waves.
It's important to note that although a moving-coil microphone requires a conductive material to move within a magnetic field, the diaphragm itself is not electrically conductive.
Sound waves cause increases and decreases in ambient pressure. A dynamic mic diaphragm will be exposed at one side or both sides of its diaphragm. The difference in pressure between the sides causes the diaphragm to move inward and outward from its resting position.
For much more information on microphone diaphragms, check out my article What Is A Microphone Diaphragm? (An In-Depth Guide).
Conductive Coil
The conductive component needed for electromagnetic induction (and the proper functioning of the dynamic microphone) is a coil. Usually, this coil is made of copper but can be made of other conductive materials as well.
The coil is cylindrical in shape and typically has just over half the diaphragm diameter (generally speaking). It is attached to the rear side of the diaphragm and moves along with the diaphragm in reaction to sound waves.
Magnetic Structure (Magnet + Pole Pieces)
As we can see in the diagram, the magnetic structure is quite peculiar. Let's look at another cross-sectional diagram of the moving-coil microphone's magnetic structure:
In the above diagram, we see the main ring magnet in red. This magnet resembles a hardware washer and has its south pole above its north pole in the diagram above.
The green blocks represent pole pieces, which are effectively used to extend the poles of the main magnet.
The pole piece above the magnet (also in the shape of a hardware washer) extends the magnet's south pole.
A disc-shaped pole piece is connected underneath the main magnet, extending its north pole. Another pole piece (cylindrical in shape) is connected from the bottom disc and reaches back toward the diaphragm, further extending the north pole.
No magnet will naturally hold the magnetic poles required of quality dynamic microphone designs, so pole pieces are required. The opposite magnetic poles to the interior and exterior of the conductive coil create the optimal magnetic field for electromagnetic induction.
Electrical Lead Wires
Electrical lead wires are connected to either end of the conductive coil. These wires effectively take the induced voltage across the coil and make it part of a greater circuit that ultimately leads to the microphone output.
Cartridge Housing
All these components are housed within a single unit. This unit is then designed into the microphone.
Here is a picture of a moving-coil dynamic cartridge from the top:
Above, we can see the outer housing and a clear diaphragm. The smaller inner circle is where the conductive coil attaches to the diaphragm. The interior of this circle is the pole piece. Left of centre, we see the two electrical lead wires behind the see-through Mylar diaphragm.
How Does The Moving-Coil Dynamic Cartridge Work As A Transducer?
So now that we know the inner components of the dynamic transducer, let's get into the inner workings of the dynamic microphone.
Let's start at the part of the dynamic mic common to all microphones: the diaphragm.
As sound reaches the dynamic microphone, the varying pressure will interact with the diaphragm. Some dynamic diaphragms are only exposed to sound pressure at their front side (these are considered pressure mics and have omnidirectional polar patterns). Other dynamic diaphragms are open to interacting with sound pressure at both sides of their diaphragms (pressure-gradient mics and can have any polar pattern).
Either way, the mic diaphragm moves in accordance with the sound waves around it. This is the beginning of the dynamic microphone transducer process.
As the diaphragm moves back and forth about resting position, coinciding with the sound waves, so too does the attached conductive coil.
The movement of the coil within the magnetic field (supplied by the magnetic structure) causes a voltage across the coil via electromagnetic induction. Since the diaphragm and coil move back and forth, this voltage alternates, causing an alternating current.
This AC voltage will ultimately be the microphone signal and is “taken out” of the cartridge via electrical lead wires.
This is the essential working principle of moving-coil dynamic microphones!
To learn more about mic signals and the role of magnets in dynamic mics, check out my articles What Is A Microphone Audio Signal, Electrically Speaking? and Do Microphones Need Magnetism To Work Properly? respectively.
Dynamic Microphone Design Post-Cartridge
Oftentimes the lead wires complete a circuit with an output step-up transformer (though not always).
The output transformer benefits the dynamic microphone in a few key ways:
- Increases or “steps-up” the voltage of the induced mic signal
- “Matches” the impedance of the induced mic signal voltage
- Protects the microphone from DC voltage like phantom power
- Aids in isolating the microphone from other electronic devices and RFI
Before discussing how the step-up transformer works, let's have a look at a simple diagram:
The step-up transformer is made of 3 key components:
- P: primary winding
- S: secondary winding
- MC: magnetic core
The transformer, like the moving-coil cartridge, works on the principle of electromagnetic induction. So how does it work exactly? Let's find out.
The electrical leads from the cartridge connect to the primary winding. The primary winding is a coil of conductive wire (typically copper) that winds around a magnetic core.
The AC voltage in the primary coil causes a change in the magnetic field of the magnetic core. This is caused by electromagnetic induction, and the amount of magnetic variation is a product of the number of turns the primary coil has.
All things being equal, the winding with a greater number of turns will induce more voltage or a greater change in the magnetic field.
The secondary winding is physically isolated from the primary in a separate circuit. To step up the signal's voltage, the secondary winding must have more turns than the primary.
So the primary coil, which passes the signal (voltage) of the dynamic transducer, causes a varying magnetic field in the magnetic core. This varying magnetic field then induces a larger signal across the secondary winding since the secondary winding has more turns.
The result is that the transformers step up or increase the voltage and, therefore, the audio signal's strength.
Here is a picture of the legendary Shure SM57 dynamic microphone with its 51A303 transformer:
In addition to boosting the signal strength, the transformer also increases the impedance of the AC voltage. Though lower microphone output impedances are generally considered better, the increase in impedance is typically not enough to worry about with an output transformer.
Transformers also only pass AC voltage since DC will not cause any variations in the core's magnetic field. Therefore, a transformer will effectively protect a dynamic cartridge from any DC voltage such as phantom power.
Finally, the transformer will also help isolate the microphones from other electronic devices and block RFI (radio frequency interference). This is because the primary and secondary do not physically touch one another.
To learn more about microphone transformers, check out my article What Are Microphone Transformers And What Is Their Role?
Electromagnetic Induction
So much of our discussion has included electromagnetic induction. This process is the key working principle in moving-coil dynamic microphones and deserves a full explanation in this article.
So what is electromagnetic induction? Electromagnetic induction is the production of a voltage across an electrical conductor in a changing magnetic field.
This process was first discovered by Michael Faraday in 1831 and has since been utilized in many electrical components, including dynamic microphone transducer elements and output transformers.
Electromagnetic induction can take place in 3 situations involving a conductive material and a magnetic field:
- A stationary magnetic field and a moving conductor: this is the case with a dynamic microphone cartridge
- A fixed conductor and a varying magnetic field: this is the case with a step-up transformer
- Any situation where there is relative movement between a magnetic field and a conductor
In a moving-coil dynamic microphone, the coil (electrical conductor) moves through a permanent magnetic field supplied by a mic’s permanent magnet(s). The magnetic field relative to the moving coil is changing, and so once we close a circuit with the coil (and the coil moves), we will have an electromagnetically induced current (and mic signal)!
There is a physical law that is important to our understanding of electromagnetic induction. This is Faraday’s Law of Induction.
Faraday's Law of Induction states that the electromotive force (induced voltage) in a closed circuit is proportional to the rate of change over time of the magnetic flux through that circuit.
3 factors determine the amount of voltage induced across the moving coil of a dynamic microphone via electromagnetic induction. They are:
- The number of loops in the moving-coil: by increasing the number of loops in the conductive coil, we essentially increase the number of conductors cutting through the magnetic field. The amount of induced voltage across the entire moving-coil is the sum of all the voltage in each individual loop of the coil.
- The velocity of the moving-coil: by increasing the velocity of the moving-coil, we move through the magnetic field faster and therefore have a faster rate of change of the magnetic flux.
- The strength of the magnetic field: by increasing the strength of the magnetic field, we have a greater magnetic flux when field lines are perpendicular to a given area. The potential change in magnetic flux is therefore greater.
In a microphone, the number of loops in the moving coil and the strength of the magnetic field are constants. It is, therefore, the velocity of the moving coil that determines the changing of the voltage across that moving coil.
Therefore, stronger and faster variations in sound pressure (i.e., transients) produce stronger mic signals.
General Characteristics Of A Moving-Coil Dynamic Microphone
Allow me to preface this part of the article by saying that there are many different dynamic microphones in the world, and each model has its own unique design, specifications and character. That being said, we can assume that there are some features that are common across most, if not all, dynamic microphones.
These general characteristics include:
- Relatively low price point
- Ruggedness/durability
- Poor high-end frequency response
- Low sensitivity ratings & high max SPL ratings
Relatively Low Price Point
Generally speaking, dynamic microphones are less expensive than their ribbon and condenser counterparts.
Their relatively simple design and comparatively affordable components make them cheaper to build and lowers their price point.
Ruggedness/Durability
The passive components of moving-coil mics are relatively tough. Their transducer elements are physically robust, and their circuitry is rather resistant to damage.
Dynamic microphones, in general, perform better than condensers in extreme humidity and temperature. Dynamic mics are also superior in terms of durability when compared to ribbon and condenser mics.
Poor High-End Frequency Response
High-frequency sounds have difficulty moving dynamic diaphragms, so these mics typically suffer in the high-end. Thus, their frequency responses generally have a dark colour.
For more information, check out my Complete Guide To Microphone Frequency Response (With Mic Examples).
Low Sensitivity Ratings & High Max SPL Ratings
When contrasted against condenser microphones, dynamic mics output low mic signal levels. This is because they do not have the internal amplification that comes with an active condenser.
Dynamic microphones benefit greatly from preamplifiers that are capable of supplying lots of clean gain. If a mic pre cannot supply the appropriate amount of gain to bring a dynamic mic signal up to line level without noticeable distortion, then perhaps an in-line amp is required.
A popular in-line dynamic microphone amp/activator is the Cloudlifter CL-1 (link to check the price on Amazon).
On the flip side, it's practically impossible to overload a dynamic mic with too high of a sound pressure level.
For more information, check out my articles:
• What Is Microphone Sensitivity? An In-Depth Description
• What Does A Microphone’s Maximum Sound Pressure Level Actually Mean?
Applications Of Moving-Coil Dynamic Microphones
Dynamic microphones can and are used to record and reinforce all sorts of sound sources. There are many applications for moving-coil microphones and no dynamic only applications. However, there are some noteworthy situations when moving-coil dynamic microphones typically excel.
These are:
Vocals (Live Performance)
Live vocal microphones are often dynamic microphones with cardioid polar patterns. Common examples include the industry-standard Shure SM58 and Sennheiser e835.
There are a few reasons why these microphones excel as live vocal mics:
- They are very durable and can handle the rough and tumble of life on the stage and road.
- They have lower sensitivity ratings and are less likely to pick up distant extraneous sound and more likely to capture their immediate sound sources.
- Their cardioid polar patterns and the typical coloured frequency responses allow for high gain-before-feedback.
- A presence boost is common in their frequency responses which helps to improve vocal intelligibility in a live audio mix.
Vocals (Studio Recording)
It is true that large-diaphragm condenser microphones are more popular for tracking vocals in the studio.
However, dynamic mics are often preferred in rougher recordings like hard rock and metal for their colour and low sensitivity.
Broadcasting/Podcasting
Dynamic microphones work well on voice recordings in less-than-ideal environments. Unless we're in a soundproof studio iso-booth, a dynamic microphone will often outperform on voice recordings.
This is because a dynamic mic won't be so sensitive to background noise and will, therefore, “focus” more on the intended up-close voice.
For this reason, you'll often find moving-coil dynamic mics rather than condensers in radio stations and podcast setups. These recording environments often have background noise that a low-sensitivity dynamic mic can easily mitigate.
Drums (Close-Miking)
A drum kit is made of many individual drums, and it's common to mic up each drum for a more isolated sound and greater flexibility in the mix. These drums are very loud (especially at close range), and dynamic mics are often chosen for their ability to handle this loudness without issue. Whether we're close-miking a kick, snare, tom, or another drum, a dynamic mic is often our best bet!
Instrument Amplifiers
Dynamic mics are often chosen to capture the sounds of an instrument amplifier (guitar, bass guitar, etc.). These amps often only output up to 5-6 kHz, so the high-end roll-off common to dynamic mics is not a big deal.
The dynamic mic will pick up the character of the instrument amplifier on a noisy stage without capturing all the other extraneous sound sources in any sort of detail.
Brass
Brass instruments are often best captured with dynamic microphones. This is more so the case on live performance stages than studio recordings for the same reasons as the vocal applications.
Moving-Coil Dynamic Microphone Examples
It would be a disservice not to mention a few examples when teaching you about moving-coil dynamic microphones. Let's have a look at 6 individual dynamic microphones in this section:
Let's discuss each of these 6 microphones in greater detail:
Shure SM57
The Shure SM57, amicably nicknamed the “studio workhorse,” is perhaps the most commonly used dynamic microphone in the world. This cardioid microphone is the go-to for so many instruments in both studio recording and live sound reinforcement situations. It is notably prevalent as a snare drum, tom drum, and guitar cabinet microphone.
The Shure SM57 is incredibly rugged and will virtually withstand any practical studio or live sound environment.
It has a coloured frequency response with a low and high-end roll-off ranging from 40 Hz – 15 kHz (human hearing and the audible frequency range is from 20 Hz – 20 kHz). It also features a boost in sensitivity between 4 – 10 kHz.
This type of frequency response is common in dynamic mics due to the resonance of the mic cartridge, sensitivity of the diaphragm, and inertia of the diaphragm/coil.
The Shure SM57 has a low sensitivity rating of -56.0 dBV/Pa (1.6 mV) and no specified maximum sound pressure level though some sources read 180 dB SPL.
To make things even better, the Shure SM57 is very affordable, coming in at about $100 USD brand new.
Shure SM58
The Shure SM58 is a close relative of the SM57 and is the most frequently used microphone for live vocal performances. It, too, is a cardioid moving-coil dynamic microphone.
As for frequency response, the SM58 is sensitive to sound between 50 Hz – 15 kHz with an increase in sensitivity in the vocal presence range (3 – 7 kHz). This presence boost helps tremendously in accentuating the vocals in a dense mix without cranking the gain/volume of the Shure SM58 to feedback-inducing levels.
When it comes to durability and toughness, the Shure SM57 and 58 reign supreme. These mics have been documented functioning after being frozen, lit of fire, run over by tour buses, submerged in water, and dropped from a helicopter.
The sensitivity rating of the Shure SM58 is low at -54.5 dBV/Pa (1.85 mV), which is to be expected of a dynamic microphone. Its max SPL is not specified on its sheet.
Best of all, the Shure SM58 is very affordable for both beginners and experts at around $100 USD.
Shure SM7B
The Shure SM7B is another famous dynamic microphone (Shure is one of the industry leaders in dynamic microphones).
This cardioid dynamic microphone is popular for broadcasting/podcasting and as a studio vocal microphone on harder genres of music.
This rather high-end dynamic microphone is expensive relative to other dynamic mics but is still cheaper than most high-end studio condenser microphones.
The SM7B's frequency response runs from 40 Hz – 16,000 Hz and is fairly flat within this range (though the mic is still fairly coloured). Unlike the aforementioned mics, the SM7B has switchable options in its frequency response.
The first option is a low-cut filter that reduces the low-end response of the SM7B. This roll-off helps to reduce mechanical noise, low-end rumble, and the proximity effect in the mic signal.
The second option is a presence boost switch that gently boosts the SM7B's response between about 1 kHz and 10 kHz. This boost helps to improve the mic's sensitivity to speech.
Both response switches are represented by the dotted lines in the Shure SM7B frequency response graph pictured below:
The sensitivity rating of the SM7B is 1.12 mV/Pa, which is low and typical of a moving-coil dynamic mic. Its maximum sound pressure level is not explicitly specified but is speculated to be an impractical 180 dB SPL.
Although the SM7B is most often used in relatively tame recording and broadcasting environments, it's still a very durable mic. The only issue in terms of longevity is the foam windscreen, which may need replacing from time to time.
Shure Beta 52A
The Shure Beta 52A is yet another Shure microphone and is a great example of a coloured, application-specific microphone.
This dynamic microphone has a supercardioid polar pattern and a very interesting frequency response tailored to capturing kick drums' sound.
The Shure Beta 52A is a reasonably priced microphone. It is fairly limited in its applications (mostly kick drums), but since kick drums are so popular and such important elements in music, the 52A's price is worth it in most cases.
This mic has a frequency response range of 20 Hz – 10 kHz. Let's have a look at the Beta 52A's wild frequency response graph before discussing its usefulness on kick drums:
Since the 52A is dedicated to close-miking kick drums, Shure has included multiple low-end response lines that coincide with varying amounts of proximity effect. As we see, the mic's response when positioned 3 mm (1/8″) from a sound source is much more bass-heavy than its response at a distance of 2′ away.
The other main focus of the response graph is the peak around 4 kHz. This spike in sensitivity lines up well with the beater attack of a kick drum and helps bring a kick out in the mix without boosting the gain/volume of the signal too high.
Above this peak, the response drops off rather quickly, allowing the Beta 52A to “ignore” much of the high-end cymbal bleed in the drum kit.
The Beta 52A is built to last with a toughness that Shure microphones are known for. This microphone will outlive many of its peers in a mic locker in both live and studio applications.
Since this microphone is often placed directly in front of one of the loudest instruments (kick drum), it actually benefits from a low sensitivity rating of −64 dBV/Pa (0.6 mV) and a max SPL of 174 dB.
Sennheiser MD-441 U
The Sennheiser MD-441 U is one of the more expensive dynamic mics, if not the most expensive dynamic mic on the market.
This supercardioid top-address microphone is marketed as sounding like a condenser and has a frequency response range of 30 Hz – 20 kHz, which is very wide for a dynamic mic.
Sennheiser
Sennheiser is featured in My New Microphone's Top 11 Best Microphone Brands You Should Know And Use.
Its cartridge is effectively shock-mounted, and the humbucking coil within its design dramatically reduces EMI in the mic signal.
Sennheiser’s MD-441 U featured 5-selectable high-pass filters ranging from flat down to 65 Hz (M for “music) to high-passed at 500 Hz at -12 dB/octave (S for “speech”).
For more info on microphone high-pass filters, check out my articles What Is A Microphone High-Pass Filter And Why Use One?
The 441 U also has a “brilliance” switch that engages a high-shelf boost of 5-7 dB from 2200 Hz upward.
The frequency response graph of the MD-441 U can be seen below, with all 5 switchable options drawn out:
The 441 U has a low sensitivity rating of 1.8 mV/Pa and is built with a very durable design.
Electro-Voice RE20
The Electro-Voice RE20 is one of my personal favourite dynamic microphones. It is an industry standard in broadcasting and voice recording.
The dynamic microphone has a cardioid polar pattern and Electro-Voice's patented Variable-D technology that virtually eliminates the proximity effect.
Electro-Voice
Electro-Voice is featured in My New Microphone's Top 11 Best Microphone Brands You Should Know And Use.
The frequency response of the EV RE20 is very flat for a dynamic mic and ranges from 45 Hz – 18,000 Hz. In addition to a flat response and no proximity effect, the RE20 also comes with a switchable low-cut filter to reduce the low-end response of the microphone. Here is the frequency response graph of the EV RE20:
The RE20 is affordable in most serious budgets, and the durable build of this microphone makes it an investment that will continue to perform for a very long time.
The low sensitivity rating of 1.5 mV/Pa is typical of dynamic microphones. So the RE20, like many other dynamic mics, would benefit greatly from a nice clean preamp with lots of gain.
Differences Between Dynamic And Condenser Microphones
The two main types of microphones are dynamic and condenser. We've discussed dynamic microphones in great detail in this article so far. Still, to further understand this mic type, we should contrast the typical dynamic mic against the typical condenser mic.
The first difference that pops to mind is that dynamic mics are inherently passive (they do not require power), while condenser mics are always active (they do require power).
There are many other general differences between these mic types. Let's have a look at this table for an easily digestible list of differences.
| Dynamic Microphones | Condenser Microphones | |
|---|---|---|
| Transducer Principle | Electromagnetic induction | Electrostatic principles |
| Active/Passive | Passive | Active |
| Frequency Response | Coloured | Flat/extended |
| Transient Response | Slow | Fast |
| Polar Patterns | All but bidirectional | All (especially with dual-diaphragm capsule) |
| Sensitivity | Low | High |
| Self-Noise | No | Yes |
| Maximum Sound Pressure Level | Often too high to measure | Often within practical limits |
| Durability | Very durable | Somewhat durable |
| Price | Inexpensive to moderate | Cheap to very expensive |
For a dedicated article focused on the differences between dynamic and condenser microphones, check out My New Microphone's Differences Between Dynamic & Condenser Microphones.
Related Questions
Does a condenser microphone need a preamp? Condenser microphones have their own internal amplifiers but still output mic level signals and require microphone preamplifiers to bring their signals up to line level for use in other audio equipment.
Do condenser mics need power? All condenser microphones (even pre-polarized electrets) are active and require power to function properly. The common denominator of active condenser mic components is the impedance converter (tube or transistor), though there can be other active components as well.
To learn more about condenser microphones, check out my article What Is A Condenser Microphone? (Detailed Answer + Examples).
Choosing the right microphone(s) for your applications and budget can be a challenging task. For this reason, I've created My New Microphone's Comprehensive Microphone Buyer's Guide. Check it out for help in determining your next microphone purchase.
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