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Mic Techniques

Mic Techniques. Duke DeJong First Assembly Production Ministry Director. Dynamic vs Condenser mics Frequency Response Directionality Mic Placement Proximity Effect The Right Mic For The Right Use. Agenda . Dynamic vs Condenser. Dynamic Mics

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Mic Techniques

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  1. Mic Techniques Duke DeJong First Assembly Production Ministry Director

  2. Dynamic vs Condenser mics Frequency Response Directionality Mic Placement Proximity Effect The Right Mic For The Right Use Agenda

  3. Dynamic vs Condenser Dynamic Mics Dynamic microphones have relatively simple construction and are therefore economical and rugged. They can provide excellent sound quality and good specifications in all areas of microphone performance. In particular, they can handle extremely high sound levels: it is almost impossible to overload a dynamic microphone. In addition, dynamic microphones are relatively unaffected by extremes of temperature or humidity. Dynamics are the type most widely used in general sound reinforcement.

  4. Dynamic vs Condenser Condenser Mics Condenser microphones are more complex than dynamics and tend to be somewhat more costly. Also, condensers may be adversely affected by extremes of temperature and humidity which can cause them to become noisy or fail temporarily. However, condensers can readily be made with higher sensitivity and can provide a smoother, more natural sound, particularly at high frequencies. Flat frequency response and extended frequency range are much easier to obtain in a condenser. In addition, condenser microphones can be made very small without significant loss of performance. Condenser mics generally require batteries or phantom power.

  5. Frequency Response Frequency Response Is the output level or sensitivity of the microphone over its operating range from lowest to highest frequency. Virtually all microphone manufacturers list the frequency response of their microphones over a range, for example 50 - 15,000 Hz. This usually corresponds with a graph that indicates output level relative to frequency. The graph has frequency in Hertz (Hz) on the x-axis and relative response in decibels (dB) on the y-axis.

  6. Frequency Response Flat Response A microphone whose output is equal at all frequencies has a flat frequency response. Flat response microphones typically have an extended frequency range. They reproduce a variety of sound sources without changing or coloring the original sound.

  7. Frequency Response Shaped Response Mics generally have a shaped response designed to enhance a sound source in a particular application. For instance, a microphone may have a peak in the 2 – 8 kHz range to increase intelligibility for live vocals. This shape is called a presence peak or rise. A microphone may also be designed to be less sensitive to certain other frequencies. One example is reduced low frequency response (low end roll-off) to minimize unwanted “boominess” or stage rumble

  8. Frequency Response

  9. Frequency Response

  10. Frequency Response Beta 87c Frequency Response

  11. Frequency Response Beta 87c Frequency Response

  12. Directionality or Pick Up Pattern Directionality (also called Pick Up Pattern) A microphone’s sensitivity to sound relative to the direction or angle from which the sound arrives. There are a number of different directional patterns found in microphone design. These are typically plotted in a polar pattern to graphically display the directionality of the microphone. The polar pattern shows the variation in sensitivity 360 degrees around the microphone, assuming that the microphone is in the center and that 0 degrees represents the front of the microphone. The three basic directional types of microphones are omnidirectional, unidirectional, and bidirectional.

  13. Directionality or Pick Up Pattern Omni Directional has equal output or sensitivity at all angles. Its coverage angle is a full 360 degrees. An omnidirectional microphone will pick up the maximum amount of ambient sound. In live sound situations an omni should be placed very close to the sound source to pick up a useable balance between direct sound and ambient sound. In addition, an omni cannot be aimed away from undesired sources such as PA speakers which may cause feedback.

  14. Directionality or Pick Up Pattern Omni Directional

  15. Directionality or Pick Up Pattern Cardioid The unidirectional microphone is most sensitive to sound arriving from one particular direction and is less sensitive at other directions. The most common type is a cardioid (heart-shaped) response. This has the most sensitivity at 0 degrees (on-axis) and is least sensitive at 180 degrees (off-axis). The effective coverage or pickup angle of a cardioid is about 130 degrees, that is up to about 65 degrees off axis at the front of the microphone. In addition, the cardioid mic picks up only about one-third as much ambient sound as an omni. Unidirectional microphones isolate the desired on-axis sound from both unwanted off-axis sound and from ambient noise.

  16. Directionality or Pick Up Pattern Cardioid

  17. Directionality or Pick Up Pattern Super Cardioid The bidirectional microphone has maximum sensitivity at both 0 degrees (front) and at 180 degrees (back). It has the least amount of output at 90 degree angles (sides). The coverage or pickup angle is only about 90 degrees at both the front and the rear. It has the same amount of ambient pickup as the cardioid. This mic could be used for picking up two opposing sound sources, such as a vocal duet.

  18. Directionality or Pick Up Pattern Super Cardioid

  19. Directionality or Pick Up Pattern Hyper Cardioid The bidirectional microphone has maximum sensitivity at both 0 degrees (front) and at 180 degrees (back). It has the least amount of output at 90 degree angles (sides). The coverage or pickup angle is less than 90 degrees at the front but slightly more pickup in the rear than a super cardioid mic. It has the same amount of ambient pickup as the cardioid. This mic could also be used for picking up two opposing sound sources, such as a vocal duet.

  20. Directionality or Pick Up Pattern Hyper Cardioid

  21. Mic Placement Mic Placement In sound reinforcement, microphones must often be located in positions where they may pick up unintended instrument or other sounds. Some examples are: individual drum mics picking up adjacent drums, vocal mics picking up overall stage noise, and vocal mics picking up monitor speakers. In each case there is a desired sound source and one or more undesired sound sources. Choosing the appropriate directional pattern can help to maximize the desired sound and minimize the undesired sound.

  22. Mic Placement Mic Placement When using floor monitors with vocal mics, the monitor should be aimed directly at the rear axis of a cardioid microphone for maximum gain-before-feedback. When using a supercardioid, however, the monitor should be positioned somewhat off to the side (55 degrees off the rear axis) for best results. Likewise, when using supercardioid or hypercardioid types on drum kits be aware of the rear pickup of these mics and angle them accordingly to avoid pickup of other drums or cymbals.

  23. Mic Placement Ambient Sound Rejection Since unidirectional microphones are less sensitive to off-axis sound than omnidirectional types they pick up less overall ambient or stage sound. Unidirectional mics should be used to control ambient noise pickup to get a cleaner mix.

  24. Mic Placement Off Axis Coloration Change in a microphone’s frequency response that usually gets progressively more noticeable as the arrival angle of sound increases. High frequencies tend to be lost first, often resulting in muddy” off-axis sound.

  25. Mic Placement Proximity Effect With unidirectional microphones, bass response increases as the mic is moved closer (within 2 feet) to the sound source. With close-up unidirectional microphones (less than 1 foot), be aware of proximity effect and roll off the bass until you obtain a more natural sound. You can roll off low frequencies on the mixer, or use a microphone designed to minimize proximity effect, or use a microphone with a bass roll off switch, or use an omnidirectional microphone (which does not exhibit proximity effect)

  26. Right Mic For The Job • Choosing the Right Mic • Experiment with both different mics and the location of the mic • Ask other sound engineers • Ask professional music stores • There is no right answer, except the one that works best for you!

  27. Resources www.shure.com www.sweetwater.com www.sennheiserusa.com Church Production Magazine(www.churchproduction.com) Technologies For Worship Magazine(www.tfwm.com)

  28. Effective Video In A Church Service Duke DeJong First Assembly Production Ministry Director Email – duke@lovethischurch.com Office – (319) 393-6353

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