Microphones for Video: Omni Directional vs. Cardioid [Reel Rebel #36]

Microphones for Video: Omni Directional vs. Cardioid [Reel Rebel #36]

Probably one of the most overlooked aspects of a video production is sound.  Picking the right microphone for the job can be a pain, mainly because different microphones pick up sound in different ways and that can cause a headache when you're playing it back later.  So, it would behoove you to understand the difference between an omni-directional and a cardioid, because not all mics are created equal.

Omni-Directional Versus Cardioid: Breaking It Down

"Omni-Drectional" and "Cardioid" refer to the pick-up pattern of a microphone.

"Omni" means "all," so no surprise, omni-directional means, "all directions."  It has a pick-up pattern shaped like a large sphere and will pick up sound from any direction.

For lavalier mics ("lapel" mics), you pretty much always want to go with omni-directional, because you never know which way you're going to need to attach the mic to the onscreen talent.  The mic's location will be dictated by the talent's wardrobe.  These mics are ideal because they will pick up the talent's dialogue, and just a little of the atmosphere.  And because they are attached to wardrobe, they can move slightly out of place and it's good to be able to pick up the sound no matter what.

"Cardioid" is partly derived from the Greek word "kardia," or "heart."  Thus it has a pick-up pattern in the shape of a heart and only picks up the sound directly in front of it.  It mostly ignores the sound coming from the sides or from the back.

These are most effective with shotgun mics.  They will pick up the sound in front and will virtually ignore all the sound from other sources.  The only problem is if the mic gets moved out of place during takes and the sound starts to become weak.

The difference between a "lav" and a "shotgun" is detailed in this episode of Reel Rebel, and shotgun mics in general are covered here.  There's even more microphone fun in this episode where the Zoom H4 is reviewed.

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View The Full Video Transcript:

Hey I’m Stephen Schweickart with this episode of the ReelRebel where we understand that researching microphones can be a long and frustrating process. So let us help you demystify that world a little further by explaining two different types, omni-direction and cardioid.

We just love throwing big words at you, don’t we? Omni-directional? Cardioid? What in the cockadoodle does that mean?! Chill out, help has arrived. The words omni-directional and cardioid refer to what is called the “pick up pattern” of a microphone, and when you break them down, the names actually make a lot of sense. Omni means “all”, so omni-directional means all directions. This type of mic has a pick up pattern shaped like a large sphere and will gather sound no matter what direction the sound is coming from. You follow?

Now cardioid is just as easy even though it sounds like a word plucked out of some alien language. Again referring to the shape of the pick up pattern, the cardioid mic picks up sound coming only from in front of it, ignoring for the most part the sound waves hitting it from the sides and rear. The pattern bows out towards the rear slightly before curving back around to the front creating a shape that looks a heck of a lot like the heart. Did you figure it out yet? Cardioid is simply the word cardio with an I-D on the end of it, and you know that the word cardio is derived from the Greek word for heart. Well, maybe you don’t know THAT much, but just know that cardio refers to something heart-related pretty much all the time, including here.

So which one do you need for your shoot? Well, as far as lavaliers go, you’ll almost always want to go with omni. When looking for a place to clip a mic onto your subject, you never know which direction it’s going to need to face since that will be dictated by the talent’s wardrobe. These create a natural sound by picking up not only the dialog, but also SOME of the atmosphere.

The cardioid pattern generally is much more effective on shotgun mics...You remember the difference between lavs and shotguns, right? This video right here? These types of mics can be held farther away from the talent since the pick up pattern can be longer rather than wide like omni mics. The problem is that they virtually negate all sound from behind and from the sides meaning that if that mic is off axis, your primary sound isn’t going to come out very well. When it comes to lavs, being pinned to your talent’s clothes and all, it’s too easy for them to get knocked out of place. Just stick with omni for your lavs and you’ll save yourself a massive headache.

If all this sounds good, go ahead and give us a like and a sub. No I don’t mean a sub sandwich, I mean a subscribe. Well, now that I think about it, I wouldn’t hate if you also gave me a sub sandwich. All this awesome acting has made me hungry.

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About the Author -
Chris Atkinson joined ReelSEO in 2011. He is a longtime film and television reviewer, and has almost two decades of experience in the theater industry. He also writes on his personal blog - http://nymoviereviews.com. View All Posts By -

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