Wireless speakers are a great concept--get rid of those nasty wires and place your speakers wherever you want. Then reality sets in: wireless speakers still need power, so they need to be tethered to a wall outlet. And if the speakers don't have a wireless receiver built-in, they need wires connecting them to one. And, typically, their sound quality ranged from barely acceptable to pretty awful. Then again, we're most accustomed to hearing the proprietary wireless speakers that come with home-theater-in-a-box systems, so the speakers themselves aren't all that great to begin with. What if somebody offered a wireless system you could use with speakers of your choice? Such products are finally starting to appear, with the Rocketfish Universal Wireless Rear Speaker Kit at the entry-level side of the market, and KEF's Universal Wireless System (reviewed here) at the top. Both use 2.4GHz radio signals to link the rear speakers of a 5.1 surround system to the wireless transmitter attached to the amplifier at the front of the room--eliminating the need to run the longest speaker cables to the back of the room, while the front left, center, and right speakers remain wired up. But unlike a lot of two-part wireless systems, where the rear receiver needs to be wired to speakers at each end of the room, the KEF Wireless System has two separate receivers--one for each speaker--so the connecting cables can be very short. The bigger advantage--and what you're really paying $600 for--is the sound quality. While the "CD-quality" description is thrown around quite a bit these days, it's safe to say that KEF comes closer to delivering on that claim than any other wireless speaker system to date.
Design and setup
The KEF Universal Wireless System is basically a three-part system: one transmitter plus two receivers. All three units are vertically oriented black slabs about 6 inches tall, each with a circular plastic base. Each module also needs its own AC power supply, and the kit includes the necessary interconnects to wire each receiver to its matching speaker, and the transmitter to the audio source.
Once you've identified which of the two different types of power supplies gets plugged into the transmitter and receivers, setup is piece of cake. Oh, there was one other little catch; at first we couldn't tell the difference between the left- and right-channel receiver modules. Turns out they are clearly marked, but it's on the undersides of their bases.
No special care is required when positioning the receiver modules and transmitter. Just connect the 5-foot-long speaker cable that comes with the KEF Wireless Transmitter to your AV receiver, plug the transmitter and two receiver modules' power supplies into AC outlets, and hook up wires between the receiver modules and your speakers. Seconds after you power up the transmitter and receiver modules, they will automatically locate each other, their flashing blue indicator lights will stop flashing, and you're good to go.
KEF claims to have developed the system's 2.4GHz wireless, HFADPCM (high-fidelity adaptive differential pulse code modulation) transmission technology with error-protection and sophisticated adaptive frequency hopping to ensure an interference-free signal. This proprietary technology is designed to change channels automatically before any errors are audible. As such, the intention is to deliver CD-quality audio that won't be affected by microwave ovens, cordless phones, or LAN routers, all of which operate on the same frequency.
Each receiver module houses a 50-watt digital amplifier to power the speaker. Speaker cables can be connected with banana jacks, spades, or bare wire ends. So as long as your speakers have standard terminals, you're good to go. Kudos to KEF for going with standardized connectors and eschewing any proprietary nonsense. (If, on the other hand, your speakers utilize proprietary connectors--such as those found on many home-theater-in-a-box systems--you'll probably need to hunt down the manufacturer's own wireless system. Most mainstream manufacturers--including Sony, Panasonic, Samsung, and LG--now offer wireless rear speaker kits, or bundle them with the systems to begin with.)