Today’s DSLR and mirrorless cameras are capable of taking high resolution video. Unfortunately, the microphones built into these cameras are woefully inadequate, and there is little question that the audio quality can’t keep pace with the video. A simple way to upgrade your audio is with an external microphone. First, you’ll want to make sure that your camera has an external microphone jack. This jack is typically an 1/8″ (3.5 mm) mini-plug and will usually be marked as “MIC” on the camera.
When shopping for a microphone you’ll notice there are basically two types: monaural (often shortened as “mono”) which has one audio track, and stereo which has two. You might think that stereo is the better choice, but there are many instances where a mono microphone will be the best option.
Directional mono microphones, often called shotguns, have a single microphone element. The microphone element is normally placed at the back end of a barrel, which has cancellation vents on both sides. This gives the microphone a narrow pickup pattern that is called super-cardioid. The result is a microphone that is most sensitive to sound coming from the direction it is pointed, while being less sensitive to sounds from the sides and rear. This directional type pickup is preferable for most dialogue and voice over applications. For example, when recording dialogue, you want the sound pickup focused on your subject, and all extraneous sounds to be reduced. This will make your subject’s voice and your recording more intelligible. Mono microphones can also pick up sounds at a greater distance than stereo microphones, again because their pickup pattern is more focused and extraneous noise is reduced.
Stereo microphones have two microphone elements, and are designed to give you a wider, more immersive sound field than mono microphones. A wide pickup pattern is preferable for most live events and when shooting outdoors. For example, if you’re recording a band with a stereo microphone, the individual musicians will be positioned in your recording as they were on the stage. With a mono microphone, all the musicians would be centered in the sound field, as if they were all playing on stage in the same exact spot. Any type of outdoor video, from a city street to a beach setting, would be enhanced with a stereo microphone. The large sound field will replicate what is being seen and heard in the video where all directional clues would be lost with a mono microphone.
When To Use Stereo Vs. Mono
To illustrate the difference between mono and stereo microphones you could use the analogy of a wide angle or zoom lens. If a park is our setting, a wide-angle lens lets us see children playing to the left and a bird in a tree to the right. Similarly, stereo mic lets us hear the children playing on the left and the bird chirping on the right, and all the other sounds in the park. But what if we want a closeup image of the bird and to better hear its song? Then a zoom lens will give us a detailed closeup image, and a mono shotgun microphone will do the same for its song.
Another way to look at it is with the example of a wedding. You would want a mono shotgun microphone to capture the couple exchanging their vows while a stereo mic would be more suitable for the reception scenes.
Choosing a Microphone
So, which should you choose: a mono or stereo microphone? If your budget allows, you may want to consider both, or you may want to consider the Azden SMX-30 Stereo/Mono Switchable Microphone. It combines the best that a mono and stereo microphone have to offer. Since the SMX-30 is really two microphones in one it can satisfy most of your on-camera audio needs.