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10.2: Microphones

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    What Are Microphones?

    Microphones are transducers of sound waves, which means they convert sound into electrical signals that can be used in analog or digital formats. There are different ways sound gets converted into electric signals. We’ll discuss the three most commonly used in video production, dynamic, condenser, and ribbon.


    Dynamic microphones are built with a diaphragm that reacts to sound. The diaphragm has a strong magnet with a wire coil around it. The magnet creates a magnetic field and when the wire moves when sound waves enter, it creates an electric signal (See figure 10.2.1).

    This diagram is described in the figure caption.
    Figure \(\PageIndex{1}\): The diaphragm magnet is wrapped in a metal coil. When sound moves the metal coil, audio signals are produced. (CC BY-SA 3.0.; Jim Dearden via Stack Exchange)

    These microphones are very sturdy and travel well (See figures 10.2.2 and 10.2.3). They are better at picking up louder sounds than softer ones, which is why news reporters use them when they report from an outside location. The microphone will be able to pick up the reporter’s voice more so than the noise around them. The same can be said for why dynamic microphones are used at music concerts. It will pick up the sound of the singer better than any of the other sounds around them.

    Example of a dynamic microphone: Thin cylindrical base that widens at the top to wire mesh.
    Figure \(\PageIndex{2}\): Dynamic microphone (CC BY 2.0; AV Hire London via flickr)
    Example of dynamic microphone: Black cylindrical shape with sound foam at the top.
    Figure \(\PageIndex{3}\): Dynamic microphone CC BY 2.0; (verchmarco via flickr)


    Condenser microphones are built with two metal plates that are charged with electricity. One plate is a fixed plate, called the backplate, and the other plate, the diaphragm, moves when sound hits it. When the distance between the two plates changes, it creates an audio signal (See figure 10.2.4).

    This diagram is described in the figure caption.
    Figure \(\PageIndex{4}\): Two plates are charged with electricity (from a battery or phantom power). When sound moves the diaphragm, the space between the plates creates an audio signal. (CC BY-SA 3.0.; Jim Dearden via Stack Exchange)

    A battery needs to be placed inside the microphone or it needs power from what it is connected to, most commonly a camera or audio recorder. Many video cameras and audio recorders (but not DSLR or mirrorless cameras) have a setting called Phantom Power. This setting tells the camera or recorder to send an electric signal to power the two plates inside the microphone. This will drain the battery of the camera or recorder a little faster than normal.

    Condenser microphones are able to pick up soft sounds much better than dynamic microphones. They are used in many productions, like studio interviews, sitcoms, and dramas (See figures 10.2.5 and 10.2.6).

    Example of condenser microphone: round capsule shaped bottom with metal grating at the top.
    Figure \(\PageIndex{5}\): Condenser microphone (CC BY-SA 2.0; anthony_goto via flickr)
    A shotgun microphone is long and thin with a windscreen on it.
    Figure \(\PageIndex{6}\): Condenser microphone (CC BY-ND 2.0; Mac Users Guide via flickr)


    Ribbon microphones are with a very thin piece of folded metal, usually aluminum, suspended in a magnetic field (usually two strong magnets). When sound waves move the metal ribbon back and forth in the magnetic field it creates an electric signal (See figure 10.2.7).

    This diagram is described in the figure caption.
    Figure \(\PageIndex{7}\): A folded piece of thin metal (the ribbon) is suspended between two magnets. When sound waves move the ribbon, an audio signal is created. (CC BY-SA 3.0,; Arne Nordmann (norro) via Wikimedia Commons)

    Most Ribbon microphones have a figure 8 or bi-direction pickup pattern because of how the ribbon is suspended. Older ribbon mics were very sensitive and easily broken, but the ribbon microphones of today are more sturdy. Care needs to be taken to prevent gust of wind or bursts of air (like when people pop their "p"s) from hitting the ribbon and stretching it out. It is best to use this mic with a pop filter like shown Figure 10.2.5 (the disk in front of the mic) or angle the mic to prevent a direct burst of air.

    Ribbon microphones are used a lot in music recording. Since ribbon microphones pick up sound much like our ears do, musical instruments sound very natural (See figures 10.2.8 and 10.2.9).

    Example handheld ribbon microphone: Thin cylindrical at the base with wide metal mesh ball on top.
    Figure \(\PageIndex{8}\): Ribbon microphone. (CC BY-NC-SA 4.0.; Beyerdynamic GmbH & Co KG via Science Museum Group)
    A capsule shaped microphone with metal mesh in the middle.
    Figure \(\PageIndex{9}\): Ribbon microphone (CC BY-NC 2.0; Wired Photostream)


    You may have noticed in the figures above that some of the microphones look similar, like the handheld dynamic in figure 10.2.2 and the handheld ribbon mic in figure 10.2.8. Similar-looking microphones can have different internal transducers. Make sure that the microphone you have has the type of transducer you need for your production.

    • 10.2.1: Microphones Used in Video Production
      Microphones come in different shapes and sizes for various production needs. Here we will look at the most commonly used microphones in video production.
    • 10.2.2: Polar Patterns
      Microphones are built to pick up sound from different directions for different production needs. Here we will review the most common pick-up patterns of microphones used in video production.

    This page titled 10.2: Microphones is shared under a CC BY-NC 4.0 license and was authored, remixed, and/or curated by Christopher Clemens (ASCCC Open Educational Resources Initiative (OERI)) .