Audio Equipment

The last several years have seen an increase of green audio equipment. As with other high-end consumer goods, the challenge is to design a product that serves two masters—creating goods that are energy-efficient and environmentally responsible, while also ensuring that performance is at a high enough standard to satisfy demanding customers. Because the initial cost of green audio equipment is likely to be higher than equipment of similar performance, the assumed customer base consists of people who already purchase high-end audio equipment, and those consumers have exacting standards.

As with cell phones, audio equipment can be designed to encourage consumers to recycle rather than dispose of the goods. Components can be built to break down easily in processing so that metals and chemicals do not become trapped in landfills.

Every year, millions of pieces of audio equipment are sold, including MP3 players and other personal media players, stereos and stereo components, speakers, and home entertainment centers, ranging from small 50-Watt devices to powerful 1,000-Watt behemoths. A fully configured high-end system for audiophiles can easily exceed 2,000 Watts. Power [Page 15]consumption varies, but unlike many appliances, audio equipment is often in use for hours every day, which translates into thousands of kilowatt-hours and hundreds of dollars in utility bills. Because high-end audio systems are composed of multiple components—for example, multiple speakers, a CD player, a tuner, woofers and subwoofers, amplifier and preamplifiers, a turntable, and an MP3 player port—there is a great deal of potential for energy inefficiency. One of the first steps toward greener audio is simplifying the system and integrating components. Integrated amplifiers can be used instead of separate amplifiers and preamplifiers. This will often lead to a better-sounding system as well: the more components that are involved in a system, and the more combinations of different brands and models of each component there are, the greater the odds are that the consumer will construct a less-than-ideal combination of those components.

Speaker efficiency is a key part of green audio and a widely misunderstood aspect of audio equipment in general. Speaker efficiency is measured in decibels (dB), a logarithmic unit of measure. A 3-dB increase in efficiency means the speaker needs only half the power. The difference between an 85-dB speaker and a 100-dB speaker, then, is that the latter uses 32 times less power than the former—a staggering difference. Casual consumers, even those spending a good deal of money on their equipment, tend to overlook this. High-efficiency speakers have not historically been valued, partly because audiophile audio systems have typically been power-hungry by definition, involving multiple inefficient components, and partly because wattage is more typically emphasized. But higher-efficiency speakers do not simply use less power, they work better with other components at a wider range of volumes without resulting in distortion. Using more efficient speakers makes for a more efficient sound system.

Another innovation leading to greener audio is the use of class D amplifiers. Once used only for low-end audio equipment like telephone handsets, class Ds have increasingly come into use across the spectrum. Traditionally, class AB amplifiers have been used in most audio equipment. Class AB amplifiers run at 15–40 percent efficiency; much more efficient class Ds run at 40–85 percent. The gain of energy efficiency means more than just a lower electric bill and fewer emissions produced: Because the wasted energy would have been shed as heat, the heat sink can be reduced or eliminated, allowing for an audio component or system with a smaller physical footprint. One of the reasons flat-screen TVs have such crisp audio is because of their use of class D amplifiers, which eliminate the need for the significant amount of space that the audio components took up in older traditional televisions. Smaller systems lead, in turn, to lower shipping costs.

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