have very low output, thereby requiring more electronic gain￿a factor that necessitates high-quality preamp electronics in order to avoid noise.

Condenser microphones

Condenser mics are the most common for studio use. A thin electrically conductive diaphragm is suspended over a back plate, forming a delicate flexible capacitor.When sound waves excite the diaphragm, the distance between the diaphragm and back plate changes￿and with it the capacitance.This capacitance change, in turn, produces a voltage change. Associated circuitry converts these variations in voltage to a signal that is sent to the preamp. The power required by this design is serviced by the 48-volt phantom power commonly found on preamps and mixer inputs.

ultra -thin diaphragm

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In condenser mics, sound waves hitting the diaphragm change the capacitance in the field between the charged diaphragm and backplate

The diaphragms of condenser microphones are made of extremely thin metal or metalized plastic similar in thickness to kitchen plastic wrap.Their thinness makes condenser mics very accurate in frequency response and extremely sensitive to transients, such as the initial crack of a drum being struck. In addition to imparting the least sonic coloration of any microphone design, the sensitivity of condensers extends much further from the source than other mics, thus allowing greater flexibility.This greater sensitivity also provides the engineer with the option of picking up more the room ambience￿a factor that can add a great deal of realism to a recording.

Condensers are more delicate than moving-coil dynamics, yet much more resilient than ribbons. Due to sensitivity to low-frequency handling noise and the delicacy of the diaphragm, condensers are invariably used in conjunction with a shock mount, and often with the addition of a pop filter. The sonic characteristics of condensers and the need for TLC make them more ideally suited for studio recording. That is not to say that condensers can￿t be used for some tasks on stage￿ just that the environment should be controlled, such as in a professional show where cables are secured, mics are shock-mounted against vibration, and the stage is restricted to professional personnel.

Since condenser construction technology is much more labor-intensive and sophisticated compared to that of dynamics, good quality condensers tend to cost comparatively more money. Condensers are excellent choices for miking vocals, acoustic guitar, piano, orchestral instruments, saxophone, percussion and sound effects. As condensers are the predominant type of microphone for studio use, this guide will focus on condenser applications.

Capsule Size

The capsule incorporates the all-important diaphragm assembly that translates sound pressure into an electric signal. Condenser capsules come in three basic sizes￿ small, medium and large. Generally speaking, frequency response is a function of diaphragm size. Consider what happens with speakers of different size. As woofers get larger, they become more efficient at producing low frequencies and less efficient at producing high frequencies. In general, the same is true as the diameters of diaphragms increase (with some caveats we￿ll cover in a minute).

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Without intervention, microphones tend to be less linear as the diaphragm size increases

Signal-to-noise ratio of the microphone as a whole generally owes in part to diaphragm size. The more surface area that a diaphragm has, the greater its potential sensitivity to sound pressure and the stronger the output signal. As a result, large diaphragms inherently exhibit much better signa-to-noise ratios than do small ones.

Choosing & Using Microphones

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M-Audio Microphone manual Capsule Size, Condenser microphones