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Super-cardioid pick-up patterns are helpful for isolating a sound source in an audio mix, especially on noisy stages in live sound applications.
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The DPA d:vote 4099V Clip Microphone for Violin and Mandolin is designed for easy single-hand mounting without risk of damaging the instrument. Its sound is optimized for strings, and the super-cardioid pick-up pattern is intended for live sound reinforcement.
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Sennheiser’s e608 dynamic microphone features a super-cardioid pick-up pattern, meaning it offers more focused, directional control than a cardioid mic.
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This cut-away of Countryman’s new I2 Instrument microphone, launching at Winter NAMM 2015, shows the operational layers of this new condenser microphone. On the rear side, there is an extra acoustical layer (light blue). All of these acoustical layers together tune the delay and response between front and back ports, forming the precise directional pattern at all frequencies (cardioid, hypercardioid, etc.).
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The Sennheiser e604 dynamic microphone offers a cardioid or directional pick-up pattern. The term cardioid is derived from the same origin as the word cardiac, since the pick-up pattern tends to be roughly heart-shaped.
Microphones are an essential element in your sound system. Since mics are the audio device that actually captures the voice or music, knowing which one to select for a particular task is critical. Also, because the rest of your sound system only modifies and amplifies what the mics “hear,” choosing quality will lead to a better end result. In this article, we'll look at various types of microphones, their similarities and differences, and how to best apply them for your services and other events.
Microphone Types and Configurations
As a broad overview, the basic microphone technologies are dynamic and condenser—the means by which the sound waves from the voice or instrument are converted into electrical impulses to be processed and amplified by the rest of the audio system. Dynamic mics move a coil of wire—attached to a thin membrane—within a magnetic field to create a current that is analogous to the sound source. Ribbon mics use a thin metallic “ribbon” suspended in a magnetic field, so they also function on a similar principle. Condensers have a thin diaphragm separated by a small air gap from an electrically charged backplate, and as the sound waves move the diaphragm closer to and farther from the backplate, the varied capacitance creates an electrical equivalent to the original sound.
Microphones offer different polar or pick-up patterns, and are selected for an application depending on where the sound source is coming from, and how much of the overall sound field you want to capture vs. attenuate or eliminate. Omnidirectional mics have the same sensitivity to audio signals coming from all directions, so will capture all the sound in a given area no matter which way they’re pointed. Directional mics have their greatest sensitivity in one direction, pointed on-axis toward the source, and attenuate the sound coming from other directions, although not uniformly, as all directional mics have off-axis lobes of greater and lesser sensitivity.
The common patterns are cardioid, supercardioid, and hypercardioid, with the latter having the tightest on-axis pattern. As an example, you might use a wider cardioid pattern for a source such as a presenter who is moving side to side when talking or when several people are sharing the same mic, and a hypercardioid with a vocalist singing right on-axis with other loud sources nearby (making sure any monitor speakers are placed in the nulls of this polar pattern). Directional mics also exhibit proximity effect, where the lower frequencies are emphasized when the mic is used close to the source.
Dynamics
Dynamic mics are the workhorses of the audio world, with the ubiquitous Shure SM58 being the prototypical image of a microphone. Since the sound waves need to move a more robust diaphragm with a voice coil connected, dynamics have a greater moving mass than a condenser or ribbon. Dynamics are typically rugged, somewhat less responsive in the very high frequencies, moderate in sensitivity (though the neodymium magnetic structure introduced in the mid-1980s by Electro-Voice added several dB to the output, and other innovations increased the high-end frequency response), and priced in the lower to mid range. They do not require phantom power, don’t typically have as accurate of an impulse response as other mic technologies, and are available in patterns from omni to hypercardioid.
Dynamics can be great for vocals and spoken word, and many of the better recent offerings have an excellent, balanced frequency response over a wide range, and articulate high frequencies. Brass instruments can benefit when mic’d with dynamics, yielding a less cutting high end compared with many condensers. Dynamic mics are widely used for larger drums such as kick, toms, and snare. Some microphone companies offer drum mic’ing kits that include a specific (and usually physically larger) mic for the kick drum, with smaller versions for the other drum positions. Electric guitar amps usually have a dynamic pointed directly at or slightly angled from one of the speakers, toward the outside of the cone; this might be a standard dynamic or a ribbon.
When selecting new microphones, consider which mic technologies and formats will best fit the particular applications, and budget for the better quality ones—given that what they hear will ultimately be what your congregation hears.
Ribbon Microphones
Ribbons are a type of dynamic microphone, in that a moving membrane within a magnetic field converts the sound waves. In this case, a thin, typically metallic “ribbon”—corrugated for durability—is suspended between the magnets, and its movement generates the electrical impulses that are reproduced via the audio system. A key advantage, according to John Jennings of Royer Labs, is that “ribbons ‘hear’ more like the human ear that other microphone types, so if you’re looking to reproduce the natural sound of the instrument, consider using a ribbon.”
Jennings suggests that ribbon mics have a very accurate frequency response and a transient response that rivals the better condensers, and that they generally are “so much more natural sounding in a digital recording environment.” One key reason is that they don’t overemphasize the higher frequencies, so when used on brass instruments and guitar amps, the resulting audio is not “overly bright” or harsh. Ribbon mics naturally have a figure-eight coverage pattern, “hearing out of the front and back, and having phenomenal rejection from the sides, top, and bottom” to eliminate bleed on the stage. Jennings says their off-axis frequency response is virtually identical to on-axis, only at a lower level, so coloration is minimized. The rear of the figure-eight pattern can be tilted, usually toward the floor, to further eliminate bleed from nearby louder instruments or monitor speakers.
Ribbon mics were traditionally thought of as delicate, and not up to the challenges of live sound reinforcement. Along with Royer Labs’ innovations such as the R-121 that could withstand high SPL environments and touring applications, others such as Audio-Technica and Shure have developed roadworthy ribbons. Audio-Technica’s Gary Boss states that A-T holds several patents surrounding this technology, including its Microlinear ribbon imprint that protects the dual ribbons from lateral flexing and distortion. The AT4081 provides a higher output level with the use of a neodymium magnet motor structure. It has the audio quality to be used for recording and the durability for live use.
John Born of Shure adds that the company’s KSM313/NE and KSM353 mics feature proprietary Roswellite “molecularly bonded film” ribbon material, which provides the tensile strength and durability to withstand high SPL applications. These mics are precisely manufactured, with each ribbon frame being optically measured and its ribbon then custom-cut with a laser to fit it exactly—to a tolerance of .001.”
Condenser Microphones
Typically, the mass of the moving diaphragm is less in a condenser, making it more sensitive to the tiny variations in air pressure, yielding better transient response and more extended high-frequency response. Some condensers have smaller diaphragms, such as with pencil condensers and miniature instrument mics, and others are larger, such as studio-style, side-fire mics. In general, smaller diaphragms provide a wider frequency and dynamic range, and the ability to handle higher SPL, but offer lower sensitivity and higher self-noise than large-diaphragm mics.
Condenser mics are often used for acoustic instruments, such as guitar, mandolin, violin, and other stringed and bowed strings, with the miniature versions mounted on the instrument. Common mic positioning with an acoustic guitar is to point it toward or slightly to the side of the bridge, or toward the juncture where the neck meets the body; directly toward the sound hole can be louder, but is more “boomy” and prone to feedback.
Reed instruments and flutes can benefit from using a condenser, with their typically smoother response. Try for balance between the instrument’s fundamental frequencies and the higher overtones, which can be harsher, and place the mic so that it picks up both the bell end and the sound from the finger holes. Large-diaphragm condensers will tend to have slightly lessened transient response, so can sound smoother with brash brass-like trumpets, and dynamics are also often used with these instruments.
Both miniature- and large-diaphragm condensers are common options for acoustic piano, often used as a pair over the sound board covering the lower and higher strings; the miniature mics are usually mounted closer to the sound board on the harp of the piano, while the others are on boom stands or other mountings suspended at a greater distance. Drum overheads are almost always pencil condensers, and other specialty percussion instruments are well reproduced with these mics’ broad frequency response and excellent transient response.
Miniature Mics
Headset mics featuring miniature condensers on a boom have become a standard for pastors and other presenters, typically connected to a wireless beltpack. When the presenter is moving and requires free hands, headsets are by far the best choice. The mic is placed close to the corner of the mouth for isolation, remains at a constant distance even with movement, and the frequency response of excellent headsets such as those from Countryman, DPA, A-T, and others is very smooth and articulate.
Omni headsets work well at these close distances, and directional headsets can provide additional isolation when more than one mic’d presenter is talking in close proximity. Lavalier mics attached to a collar or the upper chest of the presenter can also be used, although with the much greater distance and off-axis location they are difficult to use in live sound reinforcement because of feedback, vs. their use in recording or videotaping applications.
Miniature lavalier-like condensers are widely used for close-mic’ing acoustic instruments, from bowed strings to guitars to flutes and woodwinds. Both directional and omni patterns are available. Benefits include light weight, an unobtrusive presence, excellent frequency response, great transient response, high maximum SPL, and their ability to maintain a uniform distance—moving with the instrument. Omnis can be used for this close mic’ing, capturing a wider palette of an instrument’s sound while still yielding isolation.
###SUBHEAD##Making Choices
As you work with your sound system for services, experiment with the microphones you have, and think about their polar patterns and frequency response relative to the voice or instrument you’re trying to capture—so that you’re making your choices based on experience and knowledge. When selecting new microphones, consider which mic technologies and formats will best fit the particular applications, and budget for the better quality ones—given that what they hear will ultimately be what your congregation hears.
