Selecting the right polar pattern always needs to be taken into account when choosing the best microphone for your needs. You need to consider how you want the mic to pick up the sound, and very importantly, where the mic is going to be used?
Microphones are often designed with a specific purpose in mind. Some will collect the sound from all directions almost equally, while others will only focus on a single target source right in front of them.
Knowing which is best is important if you are going to get the best performance from the mic for what you need. So let’s make an in-depth comparison between Directional vs Omnidirectional Microphones.
What Is The Difference?
Well, that difference is in what we call the polar pattern. We shall look at this a little more closely as we go on. But briefly, an omnidirectional mic will collect sound equally from all directions irrespective of its position.
The Directional mic will only collect sound from the direction it is aimed at. It will cancel or at least reduce most of the background and surrounding noise.
Clearly, they have different strengths, and so you could also say weaknesses. They will work well in different environments and in different circumstances. They will produce a different type of sound.
What is a Polar Pattern?
But before we take a closer look and make comparisons between the mics, let’s pause briefly. To get a complete picture of both mics, we need to get to grips with the concept of directionality in microphones. And that area of directionality is what we call the Polar Pattern.
The concept of the Polar Pattern refers to where the microphone collects the sound from. Sometimes the sound will come from the front and other times from the back. And in some cases, from a variety of directions.
The principal difference between the omnidirectional mic and the directional mic is the polar pattern. This refers to the sensitivity of the mic to sound coming from all the different possible angles. And therefore how much signal the mic will pick up and from where it will collect it.
The Omnidirectional mic
The Omnidirectional mic or Omni will collect sound from all directions equally. However, the higher the frequency, the more directional it will become.
In its basic form, the Omni has a simpler construction than a directional mic which can give you a dynamic but cleaner sound with a flatter frequency response.
The main factor in how well the Omni picks up the sound is its proximity. Therefore with an Omni, the direction the microphone is pointed is not as important as it is with the Directional mic.
The Directional Mic
These pick up the sound from only one specific direction, usually the front, and were designed to reduce the ambient background noise to a minimum.
But, What Is the Benefit of a Polar Pattern Collecting Sound From One Source?
There are a few. But they are better for recording live sound, especially in noisy venues.
But it isn’t just noisy venues where they excel. A good directional mic can be used at a greater distance from the target source. An example of that might be a choir where all the sound is traveling forward, allowing you to record a wider spread of sound and voices.
Using a Directional mic allows the separation of the channels to be more precise. This is because the Omni is collecting sound from all over the place. If channel separation is important, then the Directional mic will be better.
Types of Directional Polar Patterns
There are five main polar patterns used in directional mics. The difference between them is how narrow the sound collection area is at the front. So, let’s take a look at the three most common options:
The Cardioid Polar Pattern
This is easily the most commonly used polar pattern, especially in recording studios for vocals. The directional characteristic means that off-axis sound will be rejected, so there will be very little overspill from other voices or instruments as well as next to no room reflections.
Even though it is the most used, it does have some potential problems. For example, there can be tonal variations on the recording if the singer changes position.
Don’t get too Close to a Cardioid
Cardioid mics can also exhibit what is called the ‘proximity effect,’ which is a boost in the bass signal if you get too close to the mic. You tend not to get that with an Omni mic. However, unless you want a really unusual vocal sound, you would never use a microphone set to omnidirectional to record a single vocal track.
Regardless of these two factors, the Cardioid Directional polar pattern is the most used. And it is considered a safe option when recording vocals in the studio. It is also a big winner when recording instruments and can handle just about everything.
The Supercardioid Pattern
As you might expect from the name, it is similar to Cardioid. But the Supercardioid has a tighter and narrower angle of sound collection than the Cardioid.
Therefore, it offers a greater rejection of sounds from the sides of the mic. But in doing so, it becomes a little more sensitive to sounds from the rear.
Better Isolation and Reduced Feedback
The Supercardioid will give you a higher level of isolation from the problems of room or ambient noise. It is also less likely to feedback than the Cardioid pattern, even when the gain level is much higher.
However, the downside is they tend not to work so well for vocals if the singer is a ‘mover.’ If they tend to move around a lot while singing, as many do, it can affect the quality of the recording. The user needs to get in that tight, narrow sound collection point and stay there, which is easier said than done for most singers. But for something static, such as a snare for a hard hi-hat hitting drummer, they are a perfect choice.
The Supercardiod is often confused with the hyper-cardioid, so let’s take a look at that.
The Hypercardioid Pattern
As you would expect, this is a mic that also offers a very directional pattern. The sound collection point is even narrower than the Supercariod and even more sensitive to sounds it is aimed at. Therefore, they have even less sensitivity at the side than cardioid or supercardioid, but do have more from the rear. These factors make them a good choice for recording any sound that is isolated and static.
The hyper-cardioid will reject virtually all of the ambient noise around it. But as I mentioned, their sound capture point is very narrow. It, therefore, isn’t very forgiving if you move out of its range even slightly.
What Can We See From All This
The first thing that is very obvious is that the real difference between them is sound collection operation. Simply put, one collects from a smaller target source. The other collects from all around the mic.
That means that you will have to choose your mic very carefully to perfectly suit what you want to do with it. But even then, there are anomalies involved. So, let’s look at some of them…
This is a word you will hear quite frequently in and around studios and in live sound engineering. You could also use the word overspill. It occurs where two or more instruments or sound sources are being played at the same time.
Maybe a guitar, a vocal, and even a violin. They might all have their individual microphones, but the mic for the vocal could also be picking up the sound from the violin. That is what is called leakage.
Sound engineers are terrified of it, and using an Omni microphone will definitely not give you the separation that is required. In that case, the Directional Cardioid, Hyper, or Supercardioid mic is the best choice because it is going to reduce the risk of overspill.
Overspill can create an ‘airy’ atmosphere to the recording. It gives the impression of the sound of a natural room and space, which in some situations can be an advantage. For example, an acoustic guitar recorded in a nice-sounding room can take on a completely different and much larger life if it is recorded with an omni as opposed to a directional microphone.
As I keep on going back to, it will depend on the circumstances of the recording as to what type of microphone or polar pattern you should use.
There are also differences in the nature of the feedback that is produced by both types of mics. The directional mic will often feedback in the higher frequencies. The majority of Omnis usually feed back in the low-frequency bass areas.
It also builds in different ways. Directional mics, if pushed too far, will suddenly feedback. Whereas the Omni mics feedback will build more slowly. However, it is best not to reach the point of feedback, of course, and every good sound engineer should always keep all levels within acceptable levels, although this can be difficult when working with live performance sound and inexperienced musicians.
Directional vs Omnidirectional Microphones – What Are The Options When Buying?
There are plenty to choose from at all prices. There will be a mic to suit you at a price that is right, that is for certain. So, here are a couple of great options.
Starting off with the Shure SM57-LC Cardioid Microphone, which is easily one of the most versatile and famous mics in history, a real workhouse that produces great results wherever it is used.
Or, for a superb Omnidirectional option, which is also very versatile, go for the Audio-Technica AT4022 Omnidirectional Condenser Microphone. Or, for a high-quality Hypercardioid option for a narrow and defined sound collection, I would recommend the Beyerdynamic M201 TG Classic Dynamic Hypercardioid Microphone.
Or for some excellent comparisons, check out our in-depth reviews of the Best Vocal Mics, the Best Dynamic Microphones, the Best Shure Microphones, the Best Microphones for Recording Rap Vocals, the Best Condenser Microphones, or the Best XLR Microphones currently on the market.
Directional vs Omnidirectional Microphones – What Should you choose?
I can’t really answer that. I can only lay down the points that might be relevant. It will depend on where and how you want to use your microphone.
I have heard it said that sound engineers in some studios use Directional Cardioid mics because they are scared. They don’t want to try something new, so they ‘run home to mama.’ And stay with what they know.
However, I think the engineers that I have known wouldn’t be labeled as scared. And they certainly wouldn’t be afraid to try something new. They used the Directional cardioid pattern because, in the circumstances, it produced the best results.
And that is what you must do, choose the mic that will give you the best results. Forget everyone else; it’s about what you want and need to get the sound you want. Directional or Omnidirectional? They both have their positives and negatives, as most things do. Choose wisely because it is going to make a difference.