When we use the term “dynamic microphone,” we typically mean “moving-coil dynamic microphone” even though ribbon mics are also dynamic. These two microphone transducer types both convert sound into audio via electromagnetic induction, though they do so differently.
What are the differences between moving-coil and ribbon dynamic microphones? In moving-coil dynamic mics, the mic signal is induced across a conductive element (coil) attached to a diaphragm. With ribbon mics, the diaphragm itself acts as the conductor. Moving-coil mics benefit from better durability, ease of use, and lower prices while ribbon mics sound much more natural.
In this article, we’ll go into depth about the key generalities of moving-coil and ribbon dynamic microphones and uncover their differences along the way!
Moving-Coil Vs. Ribbon Dynamic Microphones
Tables are an easy way to disseminate information. Let’s look at the differences between moving-coil and ribbon dynamic mics in the following table:
|Moving-Coil Dynamic Microphones||Ribbon Dynamic Microphones|
|Conductive Element||Coil attached to diaphragm||Diaphragm itself|
|Frequency Response||Coloured||Natural high-end roll-off|
|Active Or Passive||Passive||Active or passive|
|Transformer Or Transformerless||Either||Passive: always
Active: nearly always
|Polar Patterns||Omnidirectional & unidirectional, but not bidirectional||Bidirectional by default, though other patterns are achievable|
|Price||Inexpensive to moderate||Moderate to expensive|
To read more about ribbon microphones, check out my article Dynamic Ribbon Microphones: The In-Depth Guide.
To read more about moving-coil microphones, check out my article Moving-Coil Dynamic Microphones: The In-Depth Guide.
Similarities Between Moving-Coil And Ribbon Dynamic Microphones
The main similarity between moving-coil and ribbon dynamic microphones is in the name: they are both dynamic.
Now, when most people use the term “dynamic microphone,” they really mean “moving-coil dynamic microphone.” Ribbon microphones are also dynamic but are distinguished as their own type by their ribbon-like diaphragms.
So what does dynamic mean? Simply put, a dynamic microphone transducer works on the principle of electromagnetic induction.
A conductive diaphragm (whether that’s a coil of copper attached to a diaphragm or an aluminum ribbon diaphragm) moves within a permanent magnetic field. As the conductive material oscillates back and forth, it experiences a changing magnetic field relative to its position.
For more information on microphone diaphragms, check out my article What Is A Microphone Diaphragm?
This changing magnetic field induces an AC voltage (mic signal) across the oscillating conductive material via electromagnetic induction.
Moving-coil and ribbon dynamic mics are also both passive by nature. These microphones do not require any external power to function properly. That being said, there are some ribbon mic models that have active components to help boost their signals, which we’ll get to later.
With these commonalities out of the way, let’s dive into the differences between moving-coil and ribbon microphones in more detail.
As we’ve discussed, moving-coil and ribbon dynamic microphone transducers both work on the principle of electromagnetic induction.
This means that both mic types have a conductive element in their diaphragm that oscillates within a magnetic field in order to produce the mic signal.
Moving-coil dynamic microphones have a conductive coil attached to their diaphragm.
Here is a simplified diagram of a moving-coil dynamic cartridge:
The diaphragm of a moving-coil dynamic microphone is not, by itself, conductive.
These microphones are designed with a diaphragm (typically circular and stretched along the circumference of the capsule/cartridge). Attached to this diaphragm is a conductive coil, which is most often made of copper.
So as the diaphragm moves, the coil moves with it and a mic signal is induced.
Ribbon dynamic microphones have a conductive ribbon-like diaphragm.
Here is a simple diagram of a ribbon microphone baffle:
Unlike the moving-coil mic, the ribbon dynamic microphone’s entire diaphragm is conductive.
Ribbon mics, as the name suggests, have long conductive and corrugated ribbon-like diaphragms. These diaphragms are typically made of aluminum.
As the diaphragm moves according to the sound waves around it, it experiences a difference in the magnetic field around it and a mic signal is induced.
Sensitivity is an important mic specification. It essentially tells us how strong a mic signal will be at a given sound pressure level. In other words, how effective is the microphone, from the diaphragm to output, as a converter of sound to audio.
Passive dynamic microphones are typically low in sensitivity. However, there are a few general differences to note between moving-coil and ribbon dynamic mics.
Moving-coil dynamic microphone are not very sensitive.
Moving-coil dynamic microphones are overwhelmingly passive and so there is no real amplification that happens within the mic to boost its signal.
Combine this with the fact that the amount of electromagnetic induction possible in a dynamic mic capsule/cartridge is very little. The tiny movements of the diaphragm; the small size and number of turns in the coil; and the relatively low strength of the magnetic field all play a role in determining the amount of mic signal the transducer can induced.
Therefore, the typical moving-coil dynamic mic will have low sensitivity.
Even with the boost of a step-up transformer at the output (which not all dynamic mics possess), the sensitivity will still be relatively low.
In other words, moving-coil dynamic microphone signals will need high levels of clean gain in order to get boosted to professional line level for use in pro audio equipment.
To learn more about mic level and line level signals, check out my article Do Microphones Output Mic, Line, Or Instrument Level Signals?
Ribbon microphone are even less sensitive.
Passive ribbon microphones are generally even less sensitive than their moving-coil counterparts.
This is mostly due to the following generalities:
- A thin aluminum ribbon diaphragm is a poorer conductor than the copper coil.
- The ribbon experiences less change in the ribbon mic’s magnetic field than the copper coil does in the moving-coil mic.
However, some ribbon microphones are active and have internal amplifiers (or pseudo-amplifiers such as tubes and FETs) that boost the mic signal before the output, effectively increasing the microphone’s sensitivity.
Active ribbon microphones require much less gain in order to get boosted to professional line level.
For a deeper look into microphone sensitivity, check out my article What Is Microphone Sensitivity? An In-Depth Description.
Transients are abrupt but strong bursts of sound energy. They are often associated with hits of percussion instruments, though many sounds will have some sort of transient at their beginning.
Transient response, therefore, is the microphone’s ability to respond to and accurately recreate these short but powerful sounds as audio.
Moving-coil dynamic microphones have slow transient responses.
The conductive coils and relatively thick diaphragms needed to hold them are quite heavy. This leads to a slower reaction time for moving-coil dynamic microphone diaphragms due to inertia.
This is not to say that dynamic microphones are not accurate. However, their relatively slow transient responses cause an almost compressed sounding mic signal. The diaphragms are slower to react to transients and also take longer to return to rest position after having been moved.
Ribbon microphones have very natural transient responses.
The diaphragms of ribbon microphones are extremely thin and suspended rather loosely within their baffles. This combination allows the ribbon mic to react very naturally to sound wave transients.
The ribbon diaphragm light so it is easy to move. It returns to resting position quickly since it isn’t so tightly tensioned and because it is lightweight.
Ribbon diaphragms do not sound compressed nor do they portray “overshoot,” where diaphragms overreact to transient information in sound waves.
When it comes to frequency response, or what I like to sometimes call frequency-specific sensitivity, dynamic microphones are generally a bit coloured.
A coloured frequency response means there are differences in a mic’s sensitivity along the audible spectrum of audio frequencies (20 Hz – 20,000 Hz). Some frequencies are represented more than others in the mic’s signal.
Moving-coil dynamic microphones have relatively limited and coloured frequency responses.
Moving-coil dynamic mic typically have very poor top-end response. It’s not uncommon for a moving-coil mic to have a steep high-end roll-off under 15 kHz.
Moving-coil pics also tend to have noticeable peaks and valleys within their frequency response range. These peaks are often preferred in certain applications where the sound source’s characteristic frequencies line up with the peaks of the mic.
The reasons for colouration are that moving-coil diaphragms are heavy; have strange resonant frequencies; are oddly-shaped; often have complex acoustic labyrinths; and high-end frequencies have a difficult time moving the diaphragm. All these factors lead to the non-linear coloured frequency response of moving-coil dynamic microphones.
Ribbon microphones have relatively flat frequency responses with gradual, natural-sounding high-end roll-offs.
Ribbon microphones tend to have fairly flat frequency responses with a characteristic gentle, natural-sounding roll-off of high-end frequencies.
Due to their relative looseness, ribbon diaphragms tend to have resonant frequencies well below the audible range. This alleviates any resonance peak in the audible frequency response.
The characteristic high-end roll-off is a natural occurrence since high-frequencies naturally have greater difficulty causing movement in a mic diaphragm.
For an in-depth read on microphone frequency response, check out my article Complete Guide To Microphone Frequency Response (With Mic Examples).
All dynamic microphones are, by default, passive. They require no active components to properly act as transducers. That being said, we should discuss the potential differences between moving-coil and ribbon dynamic mics when it comes to being active or passive.
Dynamic microphones are nearly always passive.
Dynamic mics work on electromagnetic induction which requires no power. The overwhelming majority of moving-coil dynamic microphones are simple and require no active components.
Even step-up transformers, which are commonly used to boost the output signal in dynamic mics, are passive and require no power.
The only time moving-coil dynamic mics use active components is when moving-coil capsules/cartridges are used within digital/USB microphones. In these cases, the internal analog-to-digital convert (and the optional headphone amp) require power to function, making these dynamic mics active.
Ribbon microphones are typically passive.
Ribbon mics are dynamic and work on electromagnetic induction, too. These mics also typically have passive output transformers.
A relatively simple circuit of the ribbon baffle and the output-coupled transformer makes up a great number of ribbon microphones.
The caveat here is that some ribbon mics are designed with active components to help boost their relatively weak mic signals. Active components include vacuum tubes, printed circuit boards, amplifiers, and even impedance converters that are designed within a microphone with a ribbon diaphragm/baffle transducer.
To read more about the differences between active and passive microphones, check out my article Do Microphones Need Power To Function Properly?
Transformer Or Transformerless?
Transformers are often included in the design of microphone outputs. They act to balance the mic signal; step-up or step-down the voltage (mic signal strength); adjust the output impedance of the signal to proper levels; and protect the microphone from DC voltages like DC bias and phantom power.
Moving-coil dynamic microphones sometimes have transformers.
Though it’s true that many moving-coil dynamic mics have output transformers, it’s also true that many models do not.
Transformers are used in moving-coil microphone design primarily to help boost the signal at the output. However, high-quality transformers are expensive and can drive up the cost of otherwise affordable microphones. Low-quality transformers are much cheaper but will add significant and often unwanted colouration and distortion to the mic signal.
The diaphragms of moving-coil mics naturally output balanced signals and are fairly resilient to DC voltage, so it’s not absolutely necessary to have an output transformer.
Those with high-quality output transformers typically sound better; have higher sensitivity; and cost more.
Moving-coil mics with low-quality transformers typically have higher sensitivity but lack clarity in their output signals.
Transformerless moving-coil dynamic mics generally have lower sensitivity ratings and their audio quality is almost fully dependent on the quality of the mic capsule/cartridge.
Nearly all ribbon microphones have transformers.
All passive ribbon microphones have step-up transformers to boost the low-level signal from the ribbon diaphragm and to help protect the microphone from DC voltage.
Active ribbon microphones, on the other hand, are often designed with balanced transformerless output circuitry rather than transformers. This circuitry acts the same as a transformer but costs much less to add to an already active mic design.
Note that active tube ribbon mics typically do have output transformers, like their tube condenser counterparts.
To read more about microphones transformers (and transistors), check out my article Do All Microphones Have Transformers And Transistors? (+ Mic Examples).
The differences in polar patterns between moving-coil and ribbon dynamic microphones are quite interesting. While ribbon mics are naturally bidirectional, moving-coil mics can easily be designed as omnidirectional or unidirectional but not bidirectional.
Dynamic mics can have any polar pattern except bidirectional.
Depending on the acoustic design of the capsule/cartridge, a moving-coil dynamic mic can have an omnidirectional or a unidirectional polar pattern.
The bidirectional polar pattern is off-limits for moving-coil mics because of the conductive coil that attaches to the back of the diaphragm.
This coil must fit inside a space within a magnetic structure and needs to be attached to the diaphragm. This means it’s impossible to have both sides of the diaphragm be the same physically and be equally exposed to sound waves.
Even if we were to design a dual-diaphragm moving-coil mic, the need for the coil and magnets would cause the diaphragms to be spaced too far apart for the mic to have a true bidirectional pattern.
Ribbon mics have a bidirectional polar pattern by default.
Most ribbon mics on the market today will have a bidirectional (figure-8) polar pattern due to the nature of their design.
This is because ribbon baffles suspend the ribbon diaphragm in a magnetic structure that hugs the perimeter of the diaphragm. The front and back of the ribbon are left open to react to sound.
In other words, the front and back of the ribbon mic diaphragm are equally sensitive to sound while the sides are not sensitive whatsoever. This effectively yields the bidirectional polar pattern.
Other polar patterns are achievable by altering the acoustic labyrinth around the diaphragm, which offsets or even stops sound from reaching one side of the ribbon diaphragm.
For more information on microphone polar patterns, check out the following My New Microphone articles: The Complete Guide To Microphone Polar Patterns and What Is A Bidirectional/Figure-8 Microphone? (With Mic Examples).
Durability is a critical factor for microphones, especially when using them in live situations or field applications. Let’s take a closer look at the general differences between moving-coil and ribbon dynamic microphone durability.
Moving-coil dynamic microphones are durable.
The design of the moving-coil cartridge is naturally tougher than the ribbon or condenser transducer elements. Their diaphragms are tougher and the mechanics that go into converting sound to audio are inherently durable (conductive coil and a magnetic structure).
To read an article on the differences between the three main microphones types, check out my article Differences Between Dynamic, Condenser, & Ribbon Microphones.
In addition to that, their simple passive circuitry is resilient to changes in temperature, humidity, and physicality.
Shure, a famous microphone manufacturer that makes the world’s greatest dynamic microphones (in my humble opinion), has several videos of their legendary SM57 and SM58 dynamic mics being put to the test.
In these videos, they set the mics on fire; freeze them; drive over them in a tour bus; and drop them from a helicopter. The results were a few dents and scratches but the microphones remained fully functional, proving the durability of [at least the two most famous] dynamic microphones on the market.
Ribbons are fairly fragile.
The thin, loosely suspended diaphragms of ribbon mics are notoriously fragile.
Of course, the passive nature of ribbon microphones makes their circuits relatively durable and resistant to changes in temperature and humidity.
But the fact remains that their diaphragms are fragile. They are easily stretched or snapped. Sharp airborne particles; plosive energy; DC voltage shorting; and dropping the mic have all been known to damage the ribbon diaphragm of ribbon mics.
On top of that, ribbon diaphragms can slowly sag over time if not cared for properly. Help to ensure the longevity of your ribbon mics by storing them standing up in protective casing.
The price points of microphone types are important to consider. Rare is the case when budget is not part of the conversation when putting together a mic locker.
Price range of moving-coil dynamic microphones:
Dynamic microphone prices range from under $10 for consumer-grade microphones to just shy of $1,000 for high-end dynamic mics.
Price range of ribbon microphones:
Ribbon microphone prices range from under $100 for consumer-grade ribbon microphones to multiple thousand dollars for the high-end (mostly active) ribbon mics and vintage models.
To read deeper into microphone pricing, check out my article How Much Do Microphones Cost? (With Pricing Examples).
What are the differences between moving-coil dynamic and condenser microphones? The main difference between dynamic and condenser mics is that dynamics convert sound to audio via electromagnetic induction while condensers do so via electrostatic principles. This leads to differences in design and overall sound. Condensers are active while dynamics are usually passive.
To learn more about the differences between moving-coil dynamic and condenser mics, check out my article Differences Between Dynamic & Condenser Microphones.
What are the differences between ribbon and condenser microphones? The main difference between ribbon and condenser mics is that ribbon mic convert sound via electromagnetic induction and condensers do so via electrostatic principles. Ribbon mics have conductive ribbon-like diaphragms and simple circuitry while condensers have active capsules and complex circuitry.
For more about the differences between ribbon and condenser mics, check out my article The Differences Between Condenser And Ribbon Microphones.