A polar pattern describes how sensitive a microphone is to sound arriving from each direction. It is set by the acoustics of the capsule, not by a filter you can add later, and it changes a recording more than the model name on the body does. Two microphones of similar quality with different patterns will produce noticeably different results in the same room. Two microphones with the same pattern, aimed the same way, will produce results that are far closer than the price difference suggests.
Where the directionality comes from
If a capsule is sealed at the back, only the pressure at the front acts on the diaphragm. Pressure is a scalar, it has no direction, so the microphone responds equally to sound from anywhere. That is an omnidirectional microphone, and it is the simplest possible design.
Open ports at the back and sound now reaches both faces of the diaphragm, arriving at the rear slightly later. The diaphragm responds to the difference between the two, which does depend on direction. That is a pressure gradient design, and every directional pattern is a variation on how the rear entry is delayed and damped. This is also the reason directional microphones exhibit proximity effect and omnidirectional ones do not.
The four patterns worth knowing
| Pattern | Deepest rejection | Room pickup | Proximity effect | Typical use |
|---|---|---|---|---|
| Omnidirectional | None | Highest | None | Lavaliers, room ambience, quiet treated spaces |
| Cardioid | Directly behind, at 180 degrees | About a third of an omni | Yes | Speech, vocals, most desk work |
| Supercardioid | Roughly 126 degrees off axis, with a small rear lobe | Slightly lower than cardioid | Stronger | Loud stages, close instrument work |
| Figure of eight | Both sides, at 90 degrees | About a third of an omni | Strongest | Two people facing each other, side rejection |
The numbers behind the table are the useful part. A cardioid is about 6 dB less sensitive at 90 degrees than straight ahead and drops away sharply behind. A supercardioid trades some of that rear null for a tighter front lobe, which is why its deepest rejection sits off to the rear sides rather than directly behind. A figure of eight has the deepest side rejection of any pattern, which makes it a precision tool for excluding one specific sound source.
Why the pattern outranks the model
In an untreated room, the ratio of direct sound to reflected sound decides how a voice reads. Moving from an omnidirectional capsule to a cardioid at the same distance cuts the reflected energy the microphone collects to roughly a third. That is a change of several decibels in the direct to reverberant ratio, and it is audible on any playback system.
Now compare that with upgrading the capsule. Audio-Technica publishes a signal to noise figure of 82 dB for the AT4040 and lists the AT2035 with a self noise figure around 10 dB. Both are cardioid, both are large diaphragm side address condensers, and the audible gap between them in a reflective room is much smaller than the gap between either of them and a badly aimed omni. The same is true of the AKG P120, published across 20 Hz to 20 kHz. Pattern and placement first, capsule second.
Proximity effect is a control, not a defect
Every directional microphone boosts low frequencies as the source gets closer. At a few inches, the lift can be substantial. Broadcast dynamics are voiced with that in mind, which is why a microphone like the Shure MV7X, published from 50 Hz to 16 kHz, sounds thin at arm’s length and full at three inches. The published response curve assumes you are close.
Handheld stage dynamics work the same way. The PylePro PDMIC78 is specified across 50 Hz to 15 kHz at 600 ohms, and a singer controls the weight of their tone simply by changing distance. If you want that control, choose a directional pattern. If you want a consistent tone regardless of how much a presenter moves, choose omni and accept the extra room.
Off axis response is the specification nobody publishes
A polar plot on a datasheet is usually drawn at a handful of frequencies, and the pattern is never equally tight across the whole range. Directionality depends on the size of the capsule relative to the wavelength, so almost every microphone becomes closer to omnidirectional at low frequencies and narrows as frequency rises. The practical consequence is that sound arriving from the side is not simply quieter, it is quieter and tonally different, usually duller.
This matters because the room reaches the capsule from every angle at once. A microphone with a smooth off axis response makes a reflective room sound like a slightly distant version of the source. One with a ragged off axis response makes the same room sound colored and hollow. It is the main reason two cardioid microphones with similar on axis curves can behave so differently in an untreated space, and it is worth reading independent polar plots rather than trusting the word cardioid alone.
Where omnidirectional wins outright
Body worn microphones are the clearest case. The wearer turns their head constantly, so a directional capsule would swing several decibels with every glance. RODE lists the Wireless PRO with an omnidirectional form factor across 20 Hz to 20 kHz on two channels, which is the standard approach for lavalier and clip on systems. The Godox Magic XT1 follows the same design logic. Omni capsules are also less sensitive to wind and clothing rustle, and they have no proximity effect, so the tone stays put as the wearer moves.
The rest of the wireless lavalier microphones category is built around this principle. If you see a directional lavalier, it is a specialist tool for a loud environment, not a general upgrade.
Pattern thinking on stage and on a drum kit
Feedback is a pattern problem before it is a gain problem. With a cardioid vocal microphone, the deepest rejection is directly behind, so a floor monitor belongs on the axis running straight back from the capsule. With a supercardioid, that spot has a small rear lobe and the true nulls sit out to the rear sides, so two wedges placed wide work better than one placed dead center. Getting this right buys several decibels of gain before feedback without touching an equalizer.
On a drum kit, pattern and placement solve the bleed problem. The Shure DMK57-52 kit pairs a kick microphone with cardioid instrument dynamics precisely so each one can be aimed to put the neighboring drum in its null. Rigid mounting matters as much as aiming, which is the entire purpose of a clamp like the Shure A56D. A capsule that drifts during a take loses the rejection you carefully set up.
A caution about listings
Marketplace specification tables frequently omit the polar pattern entirely, or put a form factor in its place. Several pages in the vocal microphones category describe a desktop dynamic using terms borrowed from shotgun or array microphones, which are different designs with different patterns. When the pattern is not stated, look it up in the manufacturer’s own datasheet before buying, because it is the single specification that will shape your recording the most.
