The Sonos Digital Music System is an interesting combination of a wired/wireless music distribution system, a wireless handheld controller, and a wireless/wired switch, in an easily upgradeable set of basic components. The devices look and feel solid - there's no cheap, light plastic on the parts that make up this system. The price, at $1199 for two Zone Players and one Sonos Controller, places it in a spot between many competing products. The price may seem high compared to products like the Netgear Wireless Digital Music Player MP101 ($129), the Actiontec Digital Media Player ($180) and similar products from D-Link and SMC. On the other hand, it is low when contrasted to commercial, very-high-end music distribution systems (like those offered by Escient and others) which have prices starting at around $1000 and quickly climbing well into the four figures.
The concept of wireless audio has been around for many years, but has yielded mostly disappointing results. Some early products used infrared (IR) to send the audio signal to wireless headsets or speakers, while others used 900 MHz or 2.4 GHz radio frequencies (RF) to transmit audio (or even video) from unit to unit. The infrared units were line-of-sight, limiting their range and installation options, and the RF units were susceptible to interference from cordless phones and other devices using the same radio frequencies. Neither were serious rivals to wired speakers connected to even a mediocre audio source.
Current wireless distribution products, like those from D-Link, Netgear, SMC and others use 802.11b or g (or 2.4 GHz consumer frequencies). These devices connect to powered speakers, stereo receivers, or TV sets (again, some of these devices can also transfer video). Manufacturers claim high quality audio, and some probably even deliver on that promise, but these devices are all limited by the strength of their wireless signals. The Sonos system uses 802.11g too, but gets around distance limitations in a way to be discussed later.