The directionality of a microphone is called its polar pattern. Different polar patterns will “pick up” sound from different directions.
The polar pattern (along with frequency response) is the most important specification of a microphone. It tells us the directional sensitivity of the microphone. There are plenty of polar pattern responses in the tens of thousands of microphones on the market.
Here is a list of all the microphone polar patterns:
Omnidirectional
Bidirectional
Cardioid
Supercardioid
Hypercardioid
Subcardioid/Wide Cardioid
Lobar/Shotgun
Boundary/PZM
Infinitely Variable*
Omnidirectional Polar Pattern
What is the omnidirectional microphone polar pattern?
A microphone with an omnidrectional polar pattern, in theory, is equally sensitive to sound in all direction. it is the polar pattern of the pressure principle.
Key Points About The Omnidirectional Polar Pattern
1. Works on the pressure principle.
2. Sensitive to sounds in all directions.
3. Resistant to vocal plosives.
4. Exhibits no proximity effect.
5. Low gain-before-feedback.
6. Least colouration to the sound.
1. Works On The Pressure Principle
Omnidirectional patterns typically work on the pressure principle. In fact, single diaphragm omnidirectional microphones provide the truest form of the pressure principle, where only the front sides of their diaphragms are exposed to external sound pressure. The rear sides of their diaphragms are closed off (in a tiny chamber at constant pressure).
Note that the omnidirectional option on many multi-pattern microphones is achieved by back-to-back cardioid capsules/diaphragms and, therefore, works on the pressure-gradient principle. These omni patterns are generally not as “truly omnidirectional” as their single-diaphragm pressure principle counterparts.
2. Sensitive To Sounds In All Directions
Omnidirectional microphones, in theory, are equally sensitive to sound from every direction. This generally holds true for lower frequencies.
However, due to the nature of high-frequency short-wavelength sounds and the physical space of the microphone body, most omnidirectional microphones become somewhat unidirectional at high frequencies.
For that reason, small omnidirectional lavalier/lapel microphones often yield the best “ideal omnidirectional” patterns.
3. Resistant To Vocal Plosives
Because omnidirectional microphones work on the pressure principle, they are very resistant to the overloading of vocal plosives.
4. Exhibits No Proximity Effect
Because omnidirectional microphones work on the pressure principle, they exhibit absolutely no proximity effect.
5. Low Gain-Before-Feedback
Since omnidirectional microphones are equally sensitive to sounds from all directions, they have no null points. Therefore, placing them around loudspeakers will be challenging.
The relatively poor gain-before-feedback of omnidirectional microphones makes them less-than-ideal for live sound reinforcement applications.
6. Least Colouration To The Sound
When trying to record the most natural sound, especially at a distance from the sound source, omnidirectional microphones are an excellent choice.
Their relative lack of off-axis colouration allow them to capture sounds from all angles accurately and naturally.
Examples Of Omnidirectional Microphones
Neumann M 50 and the Wunder Audio CM50 S cloneDPA d:screet CORE 6060Neumann KM 183
Neumann M 50 And The Wunder Audio CM50 S Clone
Bidirectional Polar Pattern
What is the bidirectional microphone polar pattern? The bidirectional microphone polar pattern is equally sensitive to sounds from the front and the back with a ring of silence at its sides. Bidirectional mics are the truest form of pressure-gradient mics and exhibit the most proximity effect. Nearly all ribbon mics are bidirectional.
Bidirectional is also known as “figure-8.”
Key Points About The Bidirectional Polar Pattern
Works on the pressure-gradient principle.
Equally sensitive to sounds from the front and back.
Ring of silence (null points) around the sides (90° & 270°).
Sensitive to vocal plosives.
Exhibits the most proximity effect.
Requires a side-address mic set up.
Standard pattern for ribbon microphones.
1. Works On The Pressure-Gradient Principle
The bidirectional microphone polar pattern is the truest form of the pressure-gradient principle, where both sides of the diaphragm are equally exposed to exterior sound pressure.
The bidirectional options in most multi-pattern microphones is also achieved with the pressure-gradient principle. However, the bidirectional option is typically created by two back-to-back cardioid capsules/diaphragms set at equal amplitudes and opposite polarity.
2. Equally Sensitive To Sounds From The Front And Back
The bidirectional microphone polar pattern means the mic is equally sensitive to sounds from the front and the back with symmetrical off-axis colouration.
The only difference between the front and back is the polarity in which the sound affects the microphone. The front of the diaphragm reacts to sound with positive polarity while the rear of the diaphragm reacts to sound with negative polarity while the rear.
3. Ring Of Silence (Null Points) Around The Sides (90° & 270°)
True bidirectional polar patterns have null points at the sides (90° and 270°). In 3D, this results in a “cone of silence” in which sounds emanating directly from the sides of the microphone are completely rejected.
This is because the sound waves that reach the bidirectional microphone from the side will hit both sides of the diaphragm simultaneously. Since the sound wave will hit each side of the diaphragm with equal force, the diaphragm will not move and no mic signal will be produced.
4. Sensitive To Vocal Plosives
Because the bidirectional polar pattern acts on the pressure-gradient principle, bidirectional mics are prone to overloading due to vocal plosives.
5. Exhibits The Most Proximity Effect
Since both sides are evenly open to external sound pressure, there’s no acoustic labyrinth impeding sound waves from reaching the rear side of the diaphragm.
Generally speaking, this means that the distance between the front and back of a bidirectional microphone is less than unidirectional mics with acoustic labyrinths. Therefore, the proximity effect would be the most present in bidirectional microphones.
Note that this isn’t necessarily the case if the bidirectional mic has a long path between the front and back of its diaphragm. However, this generality certainly holds true most of the time.
6. Requires A Side-Address Mic Setup
It’s physically impossible to achieve a true bidirectional polar pattern within a top-address microphone.
Side-address mics allow for symmetry and equal exposing of the two sides of a bidirectional capsule/cartridge/element.
7. Standard Pattern For Ribbon Microphones
The standard ribbon element is designed in a side-address setup with both sides of the ribbon diaphragm exposed to external sound pressure.
For this reason, the vast majority of ribbon microphones (though certainly not all) will have a bidirectional polar pattern.
Examples Of Bidirectional Microphones
Royer R-121AEA R84
The Royer R-121 is one of the world’s most famous ribbon microphones. We see above that its polar response is incredibly consistent along its frequency response, though it does become slighly more directional at higher frequencies.
The Royer R-121, like nearly all ribbon mics (and certainly all bidirectional mics) is side-address.
AEA R84
The AEA R84 is the Audio Engineering Associates’ clone of the legendary (but discontinued) RCA 44-BX. As we see above, the side-address bidirectional polar pattern is solid through the microphone’s frequency response.
Cardioid Polar Pattern
What is the cardioid microphone polar pattern?
The ideal cardioid microphone polar pattern is a directional pattern that is most sensitive in the mic’s on-axis direction with a null point in the exact opposite direction and a gradual attenuation in between that reaches -6 dB at 90° and 270°. The cardioid pattern is the most common polar pattern.
Cardioid is also known as “kidney” or “heart” and is often what people are referring to when using the term “unidirectional.”
Key Points About The Cardioid Polar Pattern
Works on the pressure-gradient principle.
Most commonly used polar pattern.
Very popular for vocal microphones.
Used to achieve various other patterns in multi-pattern mics.
Most sensitive to sounds in a single direction (on-axis 0°).
Null point to the rear (180°).
Roughly 6 dB less sensitive at the sides (90° & 270°).
Sensitive to vocal plosives.Exhibits proximity effect.
Excellent gain-before-feedback.
1:1 ratio of an omnidirectional and a bidirectional polar pattern.
1. Works On The Pressure-Gradient Principle
The cardioid polar pattern works on the pressure-gradient principle, where both side the diaphragm are exposed to external sound pressure.
However, with the cardioid pattern (as with all unidirectional polar patterns), the rear of the diaphragm is surrounded by an acoustic labyrinth. This series of well designed ports and acoustic dampening introduces time delay and even decreased amplitude at the rear side of the diaphragm.
The carefully tuned offset provided by the acoustic labyrinth is responsible for the specific shape of the cardioid polar pattern.
2. Most Commonly Used Polar Pattern
From vocal mics to instrument mics. From the stage to the studio to the broadcasting room. Whether it’s a large/small diaphragm, a lavalier, condenser/dynamic, cardioid mics are the most popular and commonly used microphone on Earth.
3. Very Popular For Vocal Microphones
Whether it’s a studio session, a live performance, or even a news interview on the street, cardioid microphones are the go-to for recording/reinforcing vocals (both singing and speaking).
4. Used To Achieve Various Other Patterns In Multi-Pattern Mics
The most common design-type for multi-pattern microphones involved 2 back-to-back cardioid diaphragms.
By altering the polarity and amplitude of the mic signal generated with each diaphragm, most other polar patterns are achievable.
5. Most Sensitive To Sounds In A Single Direction (On-Axis 0°)
As with all unidirectional microphones, the cardioid polar pattern is the most sensitive in a single direction (the 0° point on its polar response graph).
6. Null Point To The Rear (180°)
The cardioid polar pattern is best known for its rear-facing null point. This provides maximum rejection in the opposite direction of where a cardioid mic is pointing.
This 180° null point is highly beneficial for gain-before-feedback and positioning the microphone in live reinforcement situations.
7. Roughly 6 dB Less Sensitive At The Sides (90° & 270°)
The cardioid polar pattern gradually decreases in sensitivity from its 0° point (on-axis) to its 180° point (completely off-axis).
At its sides (90° and 270°), the ideal cardioid polar pattern is 6 decibels less sensitive to sound than it is to sounds on-axis (0°). This means the cardioid pattern is fairly rejecting of sounds to the side (6 dB difference is means half the sound intensity).
8. Sensitive To Vocal Plosives
Because the cardioid polar pattern works on the pressure-gradient principle, cardioid mics are prone to the overloading caused by vocal plosives.
9. Exhibits Proximity Effect
Although not as susceptible as a typical bidirectional microphone, cardioid mics do exhibit the proximity effect. This is due to the nature of cardioids working on the pressure-gradient principle.
10. Excellent Gain-Before-Feedback
Cardioid microphones have excellent gain-before-feedback and are the go-to microphone polar pattern for live sound reinforcement.
The best example of this is a singer during a live performance.
When the singer is stationary in from of their monitor, a cardioid mic can easily be positioned so that it points on-axis toward the singer’s mouth while simultaneously pointing away from the monitor. The rear null point of the cardioid mic will effectively reject the sound from the monitor while picking up a strong signal from the singer.
If the singer is moving, so long as he or she does not point the microphone at a monitor or other loudspeaker, the cardioid microphone should yield the best gain-before-feedback, still.
11. 1:1 Ratio Of An Omnidirectional And A Bidirectional Polar Pattern
When looking at unidirectional microphones, it’s interesting to view them as superpositions of the standard omnidirectional and bidirectional patterns.
As previously mentioned, the cardioid polar pattern is essentially a 1:1 ratio of an omnidirectional pattern combined with a bidirectional pattern.
Examples Of Cardioid Microphones
Shure SM57 and SM58Neumann
KM 184Rode NT1-A
Shure SM57 And SM58
The Shure SM57 and SM58 are likely the most popular instrument and live vocal microphone on the planet, respectively. These top-address cardioid microphones are absolute beasts and desrve their praise and popularity.
We can see that with both these microphones, at 125 Hz and below, they act more like subcardioid mics. From 500 Hz – 2,000 Hz, they are both near the ideal cardioid polar pattern. At 4,000 Hz and above, they both begin taking on a more supercardioid/hypercaridoid pattern with the rear lobe of sensitivity.
These changes in polar pattern are, again, to be expected, since microphones become more directional at higher frequencies and less directional at lower frequencies.
Neumann KM 184
The Nueamn KM 184 is getting a lot of attention in this article! This top-address small-diaphragm condenser has a beautifully consistent cardioid polar pattern.
Rode NT1-A
The Rode NT1-A is a side-address large-diaphragm condenser microphone with a cardioid polar pattern.
The Rode NT1-A has a peculiar polar response graph. It tells us that the microphone is actually more directional at 500 Hz than it is at 4,000 Hz. This is against the generality that microphones become more directional at higher frequencies.
Supercardioid Polar Pattern
What is the supercardioid microphone polar pattern? The supercardioid polar pattern is a highly directional microphone polar pattern. Ideal supercardioids are a 5:3 ratio of bidirectional to omnidirectional patterns. They are more directional than cardioids but have a rear lobe of sensitivity with null points at 127° and 233° (cone of silence).
Key Points About The Supercardioid Polar Pattern
Works on the pressure-gradient principle.
Similar to hypercardioid.
Very popular in film.
Unidirectional (most sensitive to sounds in a single direction – on-axis 0°).
Rear cone of silence: Null points to the rear (127° & 233°).
Rear lobe of sensitivity (typically -10 dB less sensitive than on-axis).
Roughly 10 dB less sensitive at the sides (90° & 270°).
Sensitive to vocal plosives.
Exhibits proximity effect.
Often the base pattern for lobar/shotgun patterns.
5:3 ratio of an omnidirectional and a bidirectional polar pattern.
1. Works On The Pressure-Gradient Principle
The supercardioid polar pattern works on the pressure-gradient principle, where both side the diaphragm are exposed to external sound pressure.
However, with the supercardioid pattern (as with all unidirectional polar patterns), the rear of the diaphragm is surrounded by an acoustic labyrinth. This series of well designed ports and acoustic dampening introduces time delay and even decreased amplitude at the rear side of the diaphragm.
The carefully tuned offset provided by the acoustic labyrinth is responsible for the specific shape of the supercardioid polar pattern.
2. Similar To Hypercardioid
Supercardioid and hypercardioid polar patterns are similar and often confused. They are both unidirectional patterns with 2 null points (a cone of silence) and a rear lobe of sensitivity.
Supercardioid is slightly less directional than hypercardioid.Supercardioid has a smaller rear lobe of sensitivity than hypercardioid.
3. Very Popular In Film
The focused directionality of supercardioid microphones make them popular choices in video production as both boom mics and camera mics. This is especially true when a supercardioid capsule is combined with an interference tube to make a lobar/shotgun polar pattern.
4. Unidirectional (Most Sensitive To Sounds In A Single Direction – On-Axis 0°)
As with all unidirectional microphones, the supercardioid polar pattern is the most sensitive in a single direction (the 0° point on its polar response graph).
5. Rear Cone Of Silence: Null Points To The Rear (127° & 233°)
The ideal supercardioid polar pattern has null points at 127° and 233°. This means there is effectively a cone of silence (sound rejection) to the rear of the microphone.
This makes supercardioids a good choice for dual foldback monitor setups in live sound performance (when these monitors are set up at 127° and 233° from the supercardioid’s on-axis line.
6. Rear Lobe Of Sensitivity (Typically -10 dB Less Sensitive Than On-Axis)
The supercardioid polar pattern has a characteristic rear lobe of sensitivity that is typically 10 decibels less sensitive than its on-axis response. This is still a fair bit of rejection, but the microphone will still pick up sound from its rear.
7. Roughly 10 dB Less Sensitive At The Sides (90° & 270°)
A 10 decibel difference in sensitivity between the 0° on-axis response and the side responses of the supercardioid polar pattern is part of the reason why this pattern is so highly directional.
8. Sensitive To Vocal Plosives
Because the supercardioid polar pattern works on the pressure-gradient principle, supercardioid mics are prone to the overloading caused by vocal plosives.
9. Exhibits Proximity Effect
Although not as susceptible as a typical bidirectional microphone, supercardioid mics do exhibit the proximity effect. This is due to the nature of supercardioids working on the pressure-gradient principle.
10. Often The Base Pattern For Lobar/Shotgun Patterns
The high directionality of the supercardioid polar pattern is often enhanced with an interference tube in order to achieve the lobar polar pattern, which is responsible for the extreme directionality of shotgun microphones.
11. 5:3 Ratio Of An Omnidirectional And A Bidirectional Polar Pattern.
The supercardioid polar pattern is essentially a 5:3 ratio of an omnidirectional pattern combined with a bidirectional pattern.
Examples Of Supercardioid Microphones
DPA d:dicate 4018ASennheiser e906
DPA d:dicate 4018A
The DPA 4018 is a top-address small-diaphragm condenser microphone. You’ll see by its polar response diagram that its polar pattern is very consistent throughout its entire frequency response.
As per usual, though, there’s a increase in directionality in the upper frequency range (16 kHz).
Sennheiser e906
The Sennheiser e906 is a side-address moving-coil dynamic microphone with a supercardioid polar pattern.
Once again, the polar response is consistent until the high-end frequencies. Because of the relatively poor upper frequency response of moving-coil dynamics (compared to condenser mics), the high-end polar response is particularly odd in the e906.
Hypercardioid Polar Pattern
What is the hypercardioid microphone polar pattern? The hypercardioid polar pattern is a highly directional mic polar pattern. Ideal hypercardioids are a 3:1 ratio of bidirectional to omni patterns. They are more directional than cardioids and supercardioids with a larger rear lobe of sensitivity and null points at 110° and 250°.
Key Points About The Hypercardioid Polar Pattern
Works on the pressure-gradient principle.
Similar to supercardioid.
Very popular in film.
Unidirectional (most sensitive to sounds in a single direction – on-axis 0°).
Rear cone of silence: Null points to the rear (110° & 250°).
Rear lobe of sensitivity (typically -6 dB less sensitive than on-axis).
Roughly 12 dB less sensitive at the sides (90° & 270°).
Sensitive to vocal plosives.Exhibits proximity effect.
Often the base pattern for lobar/shotgun patterns.
3:1 ratio of an omnidirectional and a bidirectional polar pattern.
1. Works On The Pressure-Gradient Principle
The hypercardioid polar pattern works on the pressure-gradient principle, where both side the diaphragm are exposed to external sound pressure.
However, with the hypercardioid pattern (as with all unidirectional polar patterns), the rear of the diaphragm is surrounded by an acoustic labyrinth. This series of well designed ports and acoustic dampening introduces time delay and even decreased amplitude at the rear side of the diaphragm.
The carefully tuned offset provided by the acoustic labyrinth is responsible for the specific shape of the hypercardioid polar pattern.
2. Similar To Supercardioid
Hypercardioid and supercardioid polar patterns are similar and often confused. They are both unidirectional patterns with 2 null points (a cone of silence) and a rear lobe of sensitivity.
Hypercardioid is slightly more directional than supercardioid.Hypercardioid has a larger rear lobe of sensitivity than supercardioid.
3. Very Popular In Film
The focused directionality of hypercardioid microphones make them popular choices in video production as both boom mics and camera mics. This is especially true when a hypercardioid capsule is combined with an interference tube to make a lobar/shotgun polar pattern.
4. Unidirectional (Most Sensitive To Sounds In A Single Direction – On-Axis 0°)
As with all unidirectional microphones, the hypercardioid polar pattern is the most sensitive in a single direction (the 0° point on its polar response graph).
5. Rear Cone Of Silence: Null Points To The Rear (110° & 250°)
The ideal hypercardioid polar pattern has null points at 110° and 250°. This means there is effectively a cone of silence (sound rejection) to the rear of the microphone.
This makes hypercardioids a good choice for dual foldback monitor setups in live sound performance (when these monitors are set up at 110° and 250° from the hypercardioid’s on-axis line.
6. Rear Lobe Of Sensitivity (Typically -6 dB Less Sensitive Than On-Axis)
The hypercardioid polar pattern has a characteristic rear lobe of sensitivity that is typically 6 decibels less sensitive than its on-axis response. This is still a fair bit of rejection, but the microphone will still pick up sound from its rear.
7. Roughly 12 dB Less Sensitive At The Sides (90° & 270°)
A 12 decibel difference in sensitivity between the 0° on-axis response and the side responses of the hypercardioid polar pattern is part of the reason why this pattern is so highly directional.
8. Sensitive To Vocal Plosives
Because the hypercardioid polar pattern works on the pressure-gradient principle, hypercardioid mics are prone to the overloading caused by vocal plosives.
9. Exhibits Proximity Effect
Although not as susceptible as a typical bidirectional microphone, hypercardioid mics do exhibit the proximity effect. This is due to the nature of hypercardioids working on the pressure-gradient principle.
10. Often The Base Pattern For Lobar/Shotgun Patterns
The high directionality of the hypercardioid polar pattern is often enhanced with an interference tube in order to achieve the lobar polar pattern, which is responsible for the extreme directionality of shotgun microphones.
11. 3:1 Ratio Of An Omnidirectional And A Bidirectional Polar Pattern
The hypercardioid polar pattern is essentially a 3:1 ratio of an omnidirectional pattern combined with a bidirectional pattern.
Examples Of Hypercardioid Microphones
Audix D4
Beyerdynamic M 160
Audix D4
The Audix D4 is a top-address large-diaphragm dynamic microphone.
Although the Audix D4 looks as if it has a subcardioid pattern at first glance, upon further inspection, we see that it is, in fact, a hypercardioid microphone. However, as expected, the D4 becomes more omnidirectional at lower frequencies (below 500 Hz).
Audix simply puts a great amount of detail into the above polar response graphs (0 to -36 dB in its circles).
Beyerdynamic M 160
The Beyerdynamic M 160 is a unique ribbon microphone. Not only does it feature a double ribbon, but it is also a top-address mic with a hypercardioid polar pattern.
The polar response graph of the M 160 is relatively difficult to read, but if we look closely, we can see the pattern is fairly consistent. We also see that the M 160 defies the norm and actually spreads out at its higher frequencies (8,000 Hz).
Subcardioid/Wide Cardioid Polar Pattern
What is the subcardioid/wide cardioid microphone polar pattern?
The subcardioid/wide cardioid polar pattern is a broad unidirectional pattern. Subcardioids have no null points and a 3-10 dB drop in sensitivity to the rear. The can be thought of as a superposition of omnidirectional and cardioid patterns.
Subcardioid is also known as “wide cardioid.”
Key Points About The Subcardioid/Wide Cardioid Polar Pattern
Works on the pressure-gradient principle.
Rare as a primary pattern.
Unidirectional (most sensitive to sounds in a single direction – on-axis 0°).
No null points.
Roughly 3 dB less sensitive at the sides (90° & 270°).
Roughly 10 dB less sensitive at the rear (180°).
Sensitive to vocal plosives.
Exhibits proximity effect.
7:3 ratio of an omnidirectional and a bidirectional polar pattern.
1. Works On The Pressure-Gradient Principle
The subcardioid/wide cardioid polar pattern works on the pressure-gradient principle, where both side the diaphragm are exposed to external sound pressure.
However, with the subcardioid pattern (as with all unidirectional polar patterns), the rear of the diaphragm is surrounded by an acoustic labyrinth. This series of well designed ports and acoustic dampening introduces time delay and even decreased amplitude at the rear side of the diaphragm.
The carefully tuned offset provided by the acoustic labyrinth is responsible for the specific shape of the wide cardioid polar pattern.
2. Rare As A Primary Pattern
There aren’t very many mics that are marketed as subcardioid/wide cardioid.
However, because microphones become more directional at higher frequencies and less directional at lower frequencies, we’ll often see the following:
Omnidirectional microphones begin exhibiting a subcardioid pattern at higher frequencies.Cardioid microphones begin exhibiting a subcardioid pattern at lower frequencies.
There are, of course, subcardioid or wide cardioid microphones on the market. They’re just not overly popular.
Wide cardioid is an option on some multi-pattern microphones. Notably those with a CK-12 capsule (or capsules based on the CK-12 design).
3. Unidirectional (Most Sensitive To Sounds In A Single Direction – On-Axis 0°)
As with all unidirectional microphones, the subcardioid/wide cardioid polar pattern is the most sensitive in a single direction (the 0° point on its polar response graph).
4. No Null Points
The ideal subcardioid polar pattern has no null points.
5. Roughly 3 dB Less Sensitive At The Sides (90° & 270°)
With only a 3 dB difference between the on-axis response and the side response, the wide cardioid polar pattern is fairly omnidirectional.
6. Roughly 10 dB Less Sensitive At The Rear (180°)
With a 10 dB difference between the on-axis response and the rear response, the wide cardioid polar pattern is fairly effective at rejecting rear sound sources.
This yield some isolation from rear positioned sources while maintaining a naturally capture of the sound sources in front of the subcardioid mic.
7. Sensitive To Vocal Plosives
Because the subcardioid polar pattern works on the pressure-gradient principle, wide cardioid mics are prone to the overloading caused by vocal plosives.
8. Exhibits Proximity Effect
Although not as susceptible as a typical bidirectional microphone, subcardioid mics do exhibit the proximity effect. This is due to the nature of wide cardioids working on the pressure-gradient principle.
Examples Of Subcardioid/Wide Cardioid Microphones
Microtech Gefell M 950
Schoeps MK 21 / CMC 6
Microtech Gefell M 950
The Microtech Gefell M 950 is a side-address large-diaphragm condenser with a subcardioid pattern.
As we can see above, the subcardioid polar pattern holds true across most of the microphone’s frequency response. It becomes nearly supercardioid by 8 kHz and extremely directional at 16 kHz.
Schoeps MK 21 / CMC 6
The Schoeps MK 21 is a small-diaphragm condenser capsule with a wide cardioid polar pattern. It is a module capsule that is part of Schoeps’ Colette series. This top-address capsule sounds great on the CMC 6 microphone amplifier.
As we can see above, the subcardioid polar pattern holds true across the entirety of the microphone’s frequency response. Schoeps is known for their incredibly consistent microphones and the MK 21 is no exception.
Lobar/Shotgun Polar Pattern
What is the lobar/shotgun microphone polar pattern? The lobar/shotgun polar pattern is the extremely directional polar pattern found in shotgun mics. Lobar patterns are often based on hyper or supercardioid patterns and require interference tubes to achieve their directionality. They have side and rear lobes of sensitivity.
Key Points About The Lobar/Shotgun Polar Pattern
Only achievable by physical acoustic labyrinth (interference tube).
Extension of supercardioid/hypercardioid patterns.
Works on the pressure-gradient principle.
Very common in film and television (on camera and boom poles).
Unidirectional (most sensitive to sounds in a single direction – on-axis 0°).
Most directional pattern.
Side and rear lobes of sensitivity.
Roughly 18 dB less sensitive at the sides (90° & 270°).
Roughly 10 dB less sensitive at the rear (180°).
Null points at 60°, 120°, 240°, and 300° (cones of silence).
Sensitive to vocal plosives.
Exhibits proximity effect.
1. Only Achievable By Physical Acoustic Labyrinth (Interference Tube)
You’ll notice that shotgun microphones are all relatively long and skinny. Shotgun mics are unlike most pencil microphones, which has their capsules near the end of the microphone and their electronics in the body. Instead, shotgun mics have their capsules somewhere in the middle of the overall mic body and have long interference tubes that preceed them.
An interference tube is a long slotted tube that is fitted in front of the shotgun microphone’s diaphragm. The various slots along the tube causes phase cancellation in the sound waves that enter the tube at off-axis angles.
Basically what the interference tube does is drastically increase the directionality of the microphone by rejecting most sounds that are not at a narrow angle from the mic’s on-axis line. This is the only way to achieve the lobar pattern.
2. Extension Of Supercardioid/Hypercardioid Patterns
The lobar pattern is simply a physical upgrade in directionality to the already focused supercardioid and hypercardioid patterns.
3. Works On The Pressure-Gradient Principle
Because the lobar/shotgun polar pattern is based off of unidirectional (typically supercardioid or hypercardioid) polar patterns, it, by default works on the pressure-gradient principle.
4. Very Common In Film And Television (On Camera And Boom Poles)
Because of the extreme directionality (and therefore the rejection of off-axis sounds), the lobar polar pattern has found its calling in film. It is heavily used as a boom microphone and as an on-camera mic.
5. Unidirectional (Most Sensitive To Sounds In A Single Direction – On-Axis 0°)
As with all unidirectional microphones, the lobar/shotgun polar pattern is the most sensitive in a single direction (the 0° point on its polar response graph).
6. Most Directional Pattern
As previously mentioned, the lobar/shotgun pattern is the most directional polar pattern.
7. Side And Rear Lobes Of Sensitivity
The characteristic lobar polar pattern has a strong and narrow on-axis response along with smaller side and rear lobes of sensitivity.
8. Roughly 18 dB Less Sensitive At The Sides (90° & 270°)
One consequence of the interference tube is that it generally leaves its microphone with small side lobes of sensitivity. However, an 18 decibel difference between on-axis and side sound pick up means the side sensitivity is practically negligible.
9. Roughly 10 dB Less Sensitive At The Rear (180°)
Because the lobar pattern is typically based on supercardioid and hypercardioid capsules, there will be rear lobes of sensitivity.
10. Null Points At 60°, 120°, 240°, And 300° (Cones Of Silence)
Generally speaking, the ideal lobar pattern will have 4 lobes of sensitivity (including the critical on-axis lobe) along with 4 null points (at 60°, 120°, 240°, and 300°).
11. Sensitive To Vocal Plosives
Because the lobar polar pattern works on the pressure-gradient principle, shotgun mics are prone to the overloading caused by vocal plosives.
12. Exhibits Proximity Effect
Although not as susceptible as a typical bidirectional microphone, the lobar polar pattern does exhibit the proximity effect. This is due to the nature of shotgun mics working on the pressure-gradient principle.
Examples Of Shotgun/Lobar Microphones
Sennheiser MKH 60S
choeps CMIT 5U
Sennheiser MKH 60
The Sennheiser MKH 60 is, naturally, a top-address shotgun microphone.
As we see, the lobar polar pattern’s side lobes only really show up in the higher frequencies (8,000 Hz and above). As we expect, the polar pattern shows a rear lobe of sensitivity and the null points tell us this microphone is based on a supercardioid pattern.
Schoeps CMIT 5U
The Schoeps CMIT 5U a top-address shotgun microphone.
With this microphone, we see the extreme directionality but no side lobes to explicitly tell us it’s a lobar pattern. However, we see that the polar pattern shows a rear lobe of sensitivity and the null points tell us this microphone is based on a hypercardioid pattern.
Boundary/PZM Polar Pattern
What is the boundary/PZM microphone polar pattern? The boundary/PZM microphone polar pattern is a sort of hemispherical pattern. It requires a flat surface (boundary) to eliminate rear reflections and work properly. This specialized pattern can have a capsule with any standard polar pattern.
Boundary mics are also known as “PZM (pressure zone microphones).”
Note that most boundary/PZM microphone manufacturers do not show polar response graphs. However, a typical boundary/PZM mic polar looks like the following:
Key Points About The Boundary/PZM Polar Pattern
Only achievable by physical acoustic labyrinth (flat surface).
Works on either the pressure or pressure-gradient principle (hemispherical or half-cardioid).
Very common in studio and stage.
Complete phase coherence when positioned at a boundary in an acoustic space.
1. Only Achievable By Physical Acoustic Labyrinth (Flat Surface)
The hemispherical nature of the boundary/PZM polar pattern is only achievable by a set boundary that is incredibly close to the microphone diaphragm.
The incredibly close boundary effectively eliminates the rear reflections that would otherwise cause phase issues with a microphone positioned close to a surface. This allows the boundary/PZM microphone a basically hemispherical pattern.
2. Works On Either The Pressure Or Pressure-Gradient Principle (Hemispherical Or Half-Cardioid)
Because the boundary/PZM polar pattern’s base polar response could be omnidirectional or unidirectional, these mics could work on either the pressure principle or the pressure-gradient principle, respectively.
3. Very Common In Studio And Stage
Boundary/PZM find their niche as room mics in the studio and in live sound reinforcement.
4. Complete Phase Coherence When Positioned At A Boundary In An Acoustic Space
As part of their design, pressure zone microphones have no phase issues when placed at physical boundaries. This is explained by their hemispherical polar pattern.
Examples Of Boundary/PZM Microphones
AKG C 547
BLAudio-Technica U851R
AKG C 547 BL
The AKG C 547 BL actually features a hypercardioid capsule. The resulting PZM polar pattern is designed to reject some sound from the “rear” of the microphone while remaining sensitive to the front of the microphone.
This pattern makes the AKG C 547 BL an excellent choice for tricky live sound reinforcement situations where there is a lot of extraneous noise.
Audio-Technica U851R
The Audio-Technica U851R yields are more traditional hemispherical polar pattern. Note that it is slightly less sensitive to sounds at the side.
Multi-Pattern Microphones
What is a multi-pattern microphone and which polar patterns do they have?
Multi-pattern microphones typically have dual-diaphragm capsules but may have more capsules and diaphragms. In theory, they may achieve any polar pattern by combining their capsule/diaphragm signals together in varying amplitudes and phases.
Key Points About Multi-Pattern Microphone Polar Pattern
Most commonly designed into side-address large-diaphragm condenser microphones.
Typically made from back-to-back cardioid condenser microphone diaphragms/capsules.
Various polar patterns are achievable by combining the signals of 2 or more capsules with varying amplitudes and phases.
Can be achieved via physical means (adjustable acoustic labyrinth).
Will typically have cardioid, bidirectional, and omnidirectional options. Some have only 2 options, while others have many more.
1. Most Commonly Designed Into Side-Address Large-Diaphragm Condenser Microphones
The vast majority of multi-pattern microphones are large-diaphragm side-address condenser mics.
2. Typically Made From Back-To-Back Cardioid Condenser Microphone Diaphragms/Capsules
Within these mics, there’s generally a dual-diaphragm capsule or two back-to-back capsules. Each of these typically have a cardioid pattern.
3. Various Polar Patterns Are Achievable By Combining The Signals Of 2 Or More Capsules With Varying Amplitudes And Phases
Cardioid option could be a single diaphragm’s signal with double the amplitude.Bidirectional option would be both diaphragm at equal amplitudes with opposite polarity.Omnidirectional option would be both diaphragms at equal amplitudes with equal polarity.
All other polar pattern options are simply different combinations of amplitude and polarity of the 2 (or more) mic signals.
4. Can Be Achieved Via Physical Means (Adjustable Acoustic Labyrinth)
Some microphones achieve multiple patterns with a single diaphragm by physically changing the acoustic labyrinth of the microphone.
Examples of this include the RCA 77-DX ribbon microphones with variable “back door” and the Schoeps MK 5 capsule with physical omni/cardioid switch.
5. Will Typically Have Cardioid, Bidirectional, And Omnidirectional Options.
Some mics will have only 2 options (like the aforementioned Schoeps MK 5).Many multi-pattern mics offer the 3 most popular polar patterns: omnidirectional, bidirectional, and cardioid (such as the Neumann U 87 AI).Other microphones offer plenty of options when it comes to selecting a polar pattern (like the AKG C 414 XLII).Yet others will have continuous “infinitely variable” polar patterns.
Examples Of Multi-Pattern Microphones
Neumann U 87
AIAKG C 414 XLII
Neumann U 87 AI
The Neumann U 87 AI is a side-address multi-pattern large-diaphragm condenser microphone.
It utilizes a version of Neumann’s K67 capsule, which features two back-to-back 34 mm backplates, each with its own outward-facing diaphragm.
As we see above, the U 87 AI has an omnidirectional, cardioid, and bidirectional option. The polar patterns are fairly consistent considering that the mic offers such great variety.
AKG C 414 XLII
The AKG C 414 XLII is another side-address multi-pattern large-diaphragm condenser microphone.
It utilizes a version of the famous AKG CK-12 capsule, which is known by audiophiles for its superb quality and 9-selectable polar patterns.
In the above polar response graphs, we see 5 of the 9 selectable patterns of the AKG C 414 XLII. The remaining 4 patterns are midway points between the above patterns (omnidirectional, wide cardioid, cardioid, hypercardioid, and bidirectional).
Infinitely Variable* Polar Patterns
What is an infinitely variable microphone polar pattern?
Some special multi-pattern microphones have infinitely variable mic polar patterns. These patterns are achieved either by continuous (rather than discreet) changes to the amplitudes of each diaphragm/capsule mic signal or by physical changing of an acoustic labyrinth.
Key Points About The Infinitely Variable* Polar Pattern
Available in some multi-pattern microphones.May be achieved by physical means (varying the acoustic labyrinth)May be achieved electrical means (varying the phase and amplitude relationships between two or more capsules).Infinitely variable between two polar pattens. This does not mean that any conceivable polar pattern in possible. There are limitations.
1. Available In Some Multi-Pattern Microphones
Infinitely variable microphone polar patterns make up a special subset of multi-pattern microphones that is worth mentioning.
2. May Be Achieved By Physical Means (Varying The Acoustic Labyrinth)
Like the aforementioned RCA 77-DX, some infinitely variable polar patterns are achieved by physically altering the path that sound waves must take in order to reach the rear side of the mic diaphragm.
3. May Be Achieved By Electrical Means (Varying The Phase And Amplitude Relationships Between Two Or More Capsules)
Other microphones, like the Brauner VMA, actually have continuous controls of the amplitudes of their mic signals. Blending these signals with continuously variable amplitude will lead to all sorts of interesting polar patterns.
4. Infinitely Variable Between Two Polar Pattens
Note that infinitely variable doesn’t mean we can program whatever pattern we want as a microphone’s polar response. It simply means that we can morph between the aforementioned polar patterns and arrive at interesting “midway” patterns.
Examples Of Microphones With Infinitely Variable* Polar Patterns
Brauner VMARCA 77-DX
Brauner VMA
Brauner VMA
The Brauner VMA is a side-address large-diaphragm condenser microphone. Its capsule allows for continuously variable polar patterns from Omni to Figure-8.
RCA 77-DX
The RCA 77-DX is a vintage side-address ribbon microphone. It had an interesting acoustic labyrinth with a mechanical shutter behind the ribbon. A rotary control on the back of the mic’s grille rotated a metal shutter, which affected the behavior of the labyrinth. Adjusting the shutter would gradually shift the polar pattern from the ribbon’s natural bidirectional (figure-8) polar pattern.
The RCA 77-DX has been discontinued.
Source: https://mynewmicrophone.com/the-complete-guide-to-microphone-polar-patterns/#Omnidirectional
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