M-Audio Microphone manual Backplate, Small Capsules, Medium Capsules, Large Capsules

Small Capsules

Small capsules are typically those with diaphragm diameters of less than about 1/2￿. Categorically, they are extremely accurate through the audible range of 20Hz to 20kHz. Their poor signal-to- noise ratio, however, requires tricks with electronics and relegates small capsules to being most useful for measurement rather than recording.

Medium Capsules

Medium capsules have diaphragms that are approximately 1/2 inch to 3/4￿ inch in diameter. Given the right design and manufacturing, they typically exhibit flat frequency response from about 20 to 18k. Their diaphragms are also large enough to deliver signal-to-noise ratios acceptable for professional use.

Large Capsules

Large capsules have diaphragms measuring 3/4 inch to one inch or even greater. Since larger diaphragms yield better signal-to-noise ratios and greater sensitivity without having to induce additional gain stages, bigger is typically considered better. Large capsules also tend to produce greater low frequency detail￿a quality that can￿t be measured so much as heard. Large capsules exhibit a proximity effect (most predominantly in the cardioid polar pattern), meaning that they tend to sound more ￿boomy￿ as they get closer to the source. Large diaphragm M-Audio mics include the Solaris, Luna and Nova.

The Diaphragm

The diaphragm is a critical component because it is responsible for responding directly to sound waves. The sensitivity of a mic is partially related to the thinness of its diaphragm. (Recall that the comparatively thin diaphragm of a condenser is largely what makes this type of mic much more linear and sensitive to detail than a dynamic moving-coil mic.)

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patented Disk Resonator boosts
high frequencies for full	3-micron evaporated gold
frequency response	diaphragm
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Originally, condenser diaphragms were made from very thin, light metal such as nickel. As technology evolved, it became possible to use synthetic materials such as mylar in order to create tissue-thin membranes. Since condenser diaphragms need to conduct electricity, these synthetic materials have a thin layer of gold applied to them￿the thinner, the better. Most modern condenser diaphragms are 6 to 12 microns in thickness. (A human hair is 40 microns in diameter.) The M-Audio large capsule mic, the Solaris, employs a special ultra-thin 3-micron, highly resilient mylar diaphragm. This delivers a degree of sensitivity unparalleled in the industry. (Physics dictates that we employ 6-micron diaphragms in our Luna and Nova models.)

In the old days, manufacturers would apply the gold to the diaphragm using a process known as sputtering. They would place the diaphragm substrate in a vacuum jar, atomize the gold, and then blow the gold onto one side of the material.Today￿s vacuum chambers are far superior, allowing us to use a refined technique where we place our ultra-thin mylar film in a complete vacuum and evaporate the gold in such a way that it adheres uniformly to the mylar. The result is a diaphragm that is we feel is the most sensitive in the industry.

Condenser diaphragms can be extremely sensitive to humidity and temperature changes. In order to minimize that, we temper our diaphragms by baking them for specific times at specific temperatures in order to insure maximum stability and performance.

The Backplate

In a condenser mic, the diaphragm is suspended over a backplate that carries one half of the electrical charge that results in the capacitance. The backplates of the best classic condenser microphones were made of solid brass. In an effort to cut costs, most modern manufacturers make the backplate out of injection-molded plastic and metalize them in some way. Critical listeners

Choosing & Using Microphones 5