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Why Power Matters: Beyond Amplifiers To The Big Picture

Audio people need not be electricians, but we must know how power distribution works.

For professional audio people, the word “power” usually conjures up visions of racks of amplifiers are used to drive the loudspeakers in a sound system. But the amplifier and other system components must have a stable power source from which to operate.

Thus the issue of power distribution, all the way from Hoover Dam to your sound system, is vital. Some of the principles of audio signal distribution in sound systems are borrowed directly from utility companies, and so much can be gained by taking a look at how they do it.

Most of the useful stuff in the modern world requires an energy source to operate. Several have been widely exploited, including petroleum and its derivatives, natural gas, and even atomic energy. All of these energy sources can be used to generate another form of energy that exists naturally in the environment—electricity.

Our world is teaming with energy just waiting to be harnessed. The atomic age began when scientists discovered that matter is a vast energy source. It’s mass is the “m” in E = mc2. Even a small amount of matter multiplied by the speed of light squared equals a very large “E”—which stands for energy. We don’t create energy; we transform and modify it for our own use.

An energy source has the potential for doing something that scientists call work. From our friends at dictionary.com, work is defined as, “The transfer of energy from one physical system to another, especially the transfer of energy to a body by the application of a force that moves the body in the direction of the force. It is calculated as the product of the force and the distance through which the body moves and is expressed in joules, ergs, and foot-pounds.”

Once we understand the nature of work, power is easy. Power is the rate of doing work. When electricity was first being harnessed, a common power source was the horse. A typical horse can do a certain amount of work over a certain span of time.

James Watt determined one “horsepower” to be 33,000 foot-pounds per minute. Horses can be ganged together to multiply their power, so a team of horses can out-pull a single animal.

While horses are no longer a common power source in developed countries, but horsepower lives on as a way of rating other sources. Any electrical power rating, such as watts, can also be stated in horsepower.

An important concept to grasp: power is a rate, and when properly specified it must be accompanied by words like “average” and “continuous” to be meaningful.

Most modern power sources can be used in multiples to create bigger ones, like the engines on an airplane or the amplifiers in an equipment rack. The concept is used nearly everywhere that power is generated or consumed – small sources can be used in multiples to create larger sources.

Not An Invention
Electricity is the power source of interest for producing and maintaining a modern lifestyle. It’s what makes life as we know it today possible.

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Linea Research is a leading designer and manufacturer of high performance power amplifiers and DSP controllers for the entertainment, live sound, installed sound and commercial sound markets.