If you’ve ever spoken into a microphone before, you probably know to speak into the metal grille for the best results. Chanced are you’ve spoken into a handheld microphone with a spherical grille. Microphone grilles come in many shapes and sizes and have many purposes for microphone performance!
So what is a microphone grille? A microphone grille (or “grill”) is the protective mesh-like layer around a microphone’s capsule. Grilles provide varying degrees of protection from physical trauma, plosive gusts of air, and moisture while still allowing sound to effectively enter the mic capsule.
Let’s dive into the design of microphone grilles in this article and discuss why they’re so important to microphone design!
What Are Microphone Grilles And Why Are They Important?
A microphone grille is the solid metal mesh we find around the capsule of most microphones. As mentioned, grilles are primarily designed to protect the microphone’s sensitive capsule from physical harm. The grille also offers windscreen-like effects, sheltering the capsule from gusts of air. Additionally, grilles often have an interior acoustic foam layer that will help to absorb moisture so that the capsule doesn’t get wet.
All in all, this seemingly small part of the grand microphone design is actually critical for a microphone’s longevity!
Mic grilles, like microphones, come in a variety of shapes and sizes:
Many handheld microphones like the legendary Shure SM58 dynamic microphone have ball-shaped grilles. These grilles provide superb protection to these robust live microphones.
The grille of the SM58, for example, will dent easily when subjected to severe physical trauma without acquiring sharp edges. This is all part of the design to help absorb the impact and protect the capsule (think of the grille as a car bumper and the capsule as a driver).
These “ball-shaped” grilles are not all spherical, but all approximate, to some degree, the shape of a ball (check out the Shure Beta 87A for example). Because of the popularity of these handheld microphones, they are what most people envision when they think of microphones (as was alluded to in the intro paragraph of this article).
“Pencil” microphones often employ a circular disk-like grille to protect the front of the capsule and have side-protection from the microphone body. A good example of this type of grille is found in the Neumann KM184 small-diaphragm condenser microphone.
Similar to the circular disk, other top address microphones may have a dome-shaped grille. These grilles are often designed with frequency response in mind (having specific spatial dimensions around the outer casing and the diaphragm).
A popular example of a concave up dome-shaped grille is found in the Shure SM57 dynamic microphone. I was unable to find any concave down dome-shaped microphone grilles (though nearly all “non-circular” grilles are concave down by nature).
Large-diaphragm microphones often have much larger cup-shaped grilles (for lack of a better term). Microphones such as the AKG C 414, Neumann TLM 103 and Rode NT1-A.
Even tiny lavalier microphones most often come with small detachable grilles. The two main focuses of these grilles are actually on reducing the amount of wind and handling noise as well as boosting the high-frequency response of the microphone.
Removing these grilles is often as easy a twisting them off their threaded connection. Some smaller circular shaped grilles require the removal of the entire capsule, as they are all in one piece of the microphone body. Examples, again, include the Shure SM57 and the Neumann KM 184.
Some grilles are integrated. They aren’t removable because they are consolidated within the microphone body. These types of grilles within the body of the microphone are often part of a port-like system that determines a capsule’s polar pattern. This is often the case with the long tubes of shotgun microphones.
Even though these metal mesh grilles aren’t detachable, they still act as grilles and can be considered as such. These integrated grilles often don’t have to be as robust as their detachable counterparts since the microphone body will provide much of the necessary strength and protection.
Other microphones with “integrated” grilles include the Electro-Voice RE20 dynamic, Royer R121 ribbon, and pretty well all the shotgun mics on the market.
Why Are Grilles Important?
As mentioned, the grille of a microphone is critical for the following reasons:
- To protect the microphone capsule from physical damage.
- To dissipate gusts of air from overloading the microphone capsule.
- To shield the capsule from moisture.
Let’s talk about each of these grille purposes in more detail:
Microphone Grilles And Physical Protection Of Mic Capsules
Chief among the reasons for a microphone grille is protecting the mic’s capsule from physical damage.
The capsules of moving-coil, ribbon, and condenser microphones are all designed differently. However, we may think of a capsule, generally, as the combination of the diaphragm, the diaphragm housing, and the immediate encasement of the housing.
To learn more about the differences between moving-coil, ribbon, and condenser microphones, check out my article Differences Between Dynamic, Condenser, & Ribbon Microphones.
Microphones are transducers of energy, and the change from mechanical wave energy to electrical energy happens in the capsule. Obviously, this makes capsules a vital part of the microphone.
But capsules have to be responsive to tiny variances in sound pressure. In order to capture sound accurately, diaphragms need to be very thin. The thinness of the diaphragms makes them susceptible to tearing and other damage if physically harmed. Ribbon microphone diaphragms are so sensitive that they’ve been known to be torn by dust particles they come in contact with.
Microphone grilles protect the capsules from physical trauma. Whether that’s a rare bump or touch of the grille in the studio or dropping the microphone grille down during a live performance, the grille should be designed to effectively protect the capsule!
Live purpose microphones like the Shure SM58 have very robust grilles. These grilles will actually dent if hit hard enough in order to absorb shock as well. The metal mesh grilles are also designed to not have any sharp edges when dented this way.
Studio purpose microphones like the Neumann U87 are not typically designed to be as destruction-proof as their live purpose counterparts. This is because studio microphones, generally speaking, should not have to withstand nearly as much trauma as stage and live performance microphones.
Microphone Grilles Acting As Windscreens
Another purpose of a microphone grille is to act as a windscreen. Grilles help to dissipate gusts of air that pass through them before the gust overloads the diaphragm. This protection helps reduce the amount of plosiveness (“b” and “p” popping) in the microphone signal.
To learn more about reducing plosives in your microphone signals, check out my article Top 10 Tips For Eliminating Microphone Pops And Plosives.
The mesh-like design of the grille’s shell effectively stops some of the air from reaching the capsule while deflecting (to some extent) the air that does pass through. This design allows the varying sound pressure levels to still move the diaphragm but reduces the strength of gusts of air (or wind) from overloading the diaphragm and negatively affecting the microphone signal.
Some microphone grilles have an acoustic foam attached within their interior area. This foam helps to further dissipate the gusts of air that pass through the mesh.
As an aside, pop filters also act as microphone windscreens and are typically made of metal mesh, acoustic foam, or woven nylon.
For more information on windscreens and pop filters, check out the following My New Microphone articles:
• What Are Dead Cats And Why Are Outdoor Microphones Furry?
• Best Microphone Windscreens.
• What Is A Microphone Pop Filter And When Should You Use One?
• Best Microphone Pop Filters.
Microphone Grilles And Moisture
The same foam that improves the grille’s function as a windscreen also helps to keep moisture out of the microphone capsule. The metal mesh part of some grilles also aids in the prevention of capsule moisture, but to a lesser extent.
Though not always the case, these foams are typically found in microphones for live applications rather than studio applications.
This is because with studio applications we often have the flexibility of using a pop filter and the studios themselves are usually kept pretty dry.
In live applications, we are much more likely to run into high humidity environments. When looking particularly at live vocal microphones, we must also take into consideration the amount of saliva and perspiration that will inevitably get through the metal mesh. The foam helps to absorb some of this moisture to help keep the capsule dry.
Microphone hygiene is more important to some than others. The grilles and their acoustic foams are most often removable from the microphone body. That means we can effectively clean the microphone grille and foam without running the risk of damaging the microphone.
For more information on microphones and moisture, check out my article Are Microphones Waterproof And/Or Immune To Humidity?
Microphone Grilles And Their Relation To Mic Frequency Response
Microphone grilles do, to some extent, affect a mic’s frequency response. Although not a major determining factor, I figure I’d at least mention the grille’s small role.
Grilles affect frequency response by allowing standing waves to stack up around the capsule. Think of the interior of the grilles as its own room with its own acoustic properties. Even though the “room” has an irregular shape, it will still have its own resonances.
Manufacturers often take this into account and use it to their advantage when designing their microphones. The resonances are typically high pitched due to the short wavelengths within the grille and are much less pronounced in grilles that have the aforementioned acoustic foam!
Lavalier microphones, specifically, benefit from the increased high-end frequency response that comes with their protective grilles. One lav mic could have several tiny interchangeable grilles that each provide a different resonant cavity and gentle high-frequency boost.
One such example of a lavalier mic with interchangeable grilles is the Sennheiser MKE-2 Gold (link to check the price at B&H Photo/Video).
Depending on the cap, the MKE2 will exhibit different frequency responses.
- With no capsule, the MKE2’s frequency response is relatively flat.
- The MZW cap grill (link to check the price at B&H Photo/Video) brightens the MKE2’s sound a bit.
- The MZC cap grill (link to check the price at B&H Photo/Video) brightens the MKE2’s sound even more.
A 6 dB boost around 6-8 kHz helps clarify a lav’s signal when attached near a person’s chest while a similar boost around 10-15 kHz is beneficial when the lav is attached in the hair. Grilles tend to do a better job at these boosts than post microphone equalization.
For more information on microphone frequency response, check out my article Complete Guide To Microphone Frequency Response (With Mic Examples).
Microphone Grille Materials
Microphone grilles are typically made from metal mesh “wire-cloth” formed into a specific shape. Different applications require finer or coarser mesh specifications. Often times mesh of different specs is layered two or more times to increase its effectiveness and durability. In some microphones (specifically in those for live applications), the grille has a sort of acoustic foam directly to their interior.
Brass mesh seems to be the most common material for microphone grilles. The brass mesh comes in a variety of sizes, thickness, and fineness and can be used in all layers of the grille construction. An added benefit of brass is that manufacturers can easily solder it to the microphone body if the situation calls for it.
Stage mics often have removable steel grilles. Steel provides a sturdier and more resilient material for microphone grilles. It resists physical damage better than brass and is quite resistant against breath moisture.
Some microphones, like the older AKG models (C12, C28, D12) utilize iron metal mesh. However, iron isn’t common in modern microphones.
Manufacturers of ribbon microphones may choose to avoid magnetic material for their protective grilles. Any extra magnetism could impact the highly sensitive ribbon diaphragm.
The inner acoustic foam of microphone grilles is typically made of polyurethane foam.
Will my microphone still work properly if I remove the protective grille? If the grille is detachable, the capsule will remain intact and the mic will still function. If the grille is incorporated in the body/capsule of the mic, removing the grille may also remove the capsule, rendering the mic unusable. It is not recommended to remove non-detachable grilles and capsules.
Is it ever advantageous to remove a microphone’s protective grille? No. Microphones are designed to have protective grilles. Removing the grille will leave the microphone capsule mechanically and pneumatically unprotected. It will also alter the designed frequency response of the microphone.