Wireless speakers using the 900 MHz frequency are stereo speakers that can extend stereo sound from an indoor source to the great outdoors without requiring the use of additional speaker wires. These systems utilize an electric or battery-powered transmitter to send audio signals to the speakers using wireless transmission. Most 900 MHz wireless outdoor speakers are meant to be left outside for extended periods, are waterproof, and are often designed to blend into the landscape.
The 900 MHz frequency these wireless stereo speakers utilize is the same one used by FM radio and cordless telephones. The advantage of this type of wireless transmission is that the signal can easily transmit through a building's floors and walls without distortion, as well as through outdoor obstacles such as fences, trees and shrubbery. Using the 900 MHz band also allows users to add several speakers, as is often necessary with an outdoor installation, without diluting the signal.
A clear disadvantage of using the 900 MHz frequency is interference with other devices using this band, particularly cordless phones. Therefore, the actual range of the signal can be much less than the effective range the manufacturer claims. When interference occurs, it is recommended that the user either adjust the tuner knobs on the transmitter and speakers or move the speakers closer to the transmitter until the problem abates.
Setting up 900 MHz wireless outdoor speakers entails attaching a power adapter to the transmitter and then plugging the unit into a standard household electrical outlet. Another cable is then plugged into the transmitter while the other end, which usually has two plugs, is attached to the right and left audio output jacks on a stereo receiver or television. Attaching the transmitter to a computer usually requires the use of a headphone adapter plug. The speakers are then placed within the recommended distance from the transmitter.
There are several 900 MHz wireless outdoor speakers available in various price ranges. They may be sold either as a set that often includes two speakers, a transmitter and a remote control device; or as a single speaker to expand an existing system. Most are meant to be inconspicuous and some are even designed to look like common backyard items such as rocks. A few manufacturers offer 900 MHz speakers that are designed to work very well with iPod systems and MP3 players, as well as traditional stereo systems.
Another wireless listening option is 900 MHz headphones, which work in the same way as 900 MHz wireless outdoor speakers. The advantage of these wireless headphones is that the user may move around without contending with annoying wires. The disadvantage is that moving outside of the transmitter's range will negatively impact performance, though the range of motion allowed by the wireless transmission is much greater than that experienced by users of wired headphones.