The Polk Audio Atrium 4 White Outdoor/Bookshelf Speakers are versatile and durable speakers designed to deliver high-quality sound in both indoor and outdoor environments. These speakers feature Polk Audio's Dynamic Balance technology, which ensures a rich, clean, and full-range sound with minimal distortion. This technology helps to eliminate resonances and other imperfections in the speaker drivers for accurate audio reproduction. Each Atrium 4 speaker typically includes a 4.5-inch long-throw mineral-filled polymer cone driver coupled with a 0.75-inch aluminum dome tweeter. This driver configuration allows for a wide frequency response and delivers crisp highs, clear mids, and satisfying bass. The Atrium 4 speakers are built to withstand the elements, making them ideal for outdoor use. They are resistant to moisture, UV rays, salt, and temperature extremes, ensuring long-lasting performance even in harsh outdoor environments. These speakers come with durable, rust-proof aluminum grilles and brackets, as well as a mineral-filled polypropylene cabinet that provides protection against the elements. The enclosure is designed to withstand rain, snow, and sun exposure without compromising sound quality. The Atrium 4 speakers offer flexible mounting options, allowing you to place them on a bookshelf or mount them on a wall, eave, or pole using the included brackets. This versatility makes them suitable for various indoor and outdoor applications. These speakers feature a broad sound dispersion pattern, ensuring that the audio is evenly distributed throughout the listening area. This makes them ideal for outdoor spaces where listeners may be scattered around the area. The Atrium 4 speakers typically have a recommended power range of 10-80 watts per channel, allowing them to be paired with a wide range of amplifiers or receivers. They can handle higher power levels for brief peaks without distortion. With a sensitivity typically around 89 dB, these speakers can produce ample volume levels with relatively low input power, making them efficient and suitable for use in outdoor settings where background noise may be present.