In the last couple of years, several companies have introduced digital audio receivers or media servers that enable you to stream music--and sometimes images and video--from your PC or Mac to a stereo, a TV, or a set of speakers in another room. So why has little Sonos, a start-up based in Santa Barbara, managed to attract so much attention for its relatively expensive audio-only Digital Music System? Well, because it's essentially the product everybody's been hoping Apple would make: a simple, elegant solution that's arguably the iPod of digital audio receivers. Nitpicks aside, if you have a bunch of digital audio files on a hard drive and are looking for a way to add music to several rooms in your home without going the installer route, Sonos's Digital Music System is an enticing option.

Design

The base Sonos system consists of the ZP100 ZonePlayer and the CR100 controller, a high-tech wireless remote with a sharp color screen and a touch-pad scroll wheel that's the secret sauce in this package. Take one look at the silver-and-white color scheme (and that scroll wheel), and you get the idea that Sonos wants you to think that its understatedly sleek components would fit right into Apple's iPod line--and they would.

As we said, those components aren't cheap--a single ZonePlayer goes for $499, while the remote comes in at $399--but they definitely have solid build quality. (Sonos sells an "introductory bundle" through the company's Web site consisting of two ZonePlayers and a single controller for $1,199, which saves about $200 over purchasing them separately.) The nearly button-free ZonePlayer, which houses a full-fledged 50-watt-per-channel amplifier and weighs 10 pounds with a die-cast matte aluminum enclosure, feels like a mini tank. About the size of an Xbox, Sonos designed it to be smaller than a typical stereo component (it measures 10.2 by 8.2 by 4.4 inches), so it would fit in spots that a typical component won't. It sports two pairs of high-quality speaker binding posts, analog stereo inputs and outputs (plus a subwoofer output), and a built-in four-port Ethernet switch.

That said, we wouldn't mind seeing Sonos build a unit that would more cleanly integrate into our audio rack. Our ideal alternate ZonePlayer configuration would be thinner and wider (the size of a standard 17-inch audio component) and classic black in color. We'd also drop the built-in amplifier (since our existing system's A/V receiver would handle the amplification needs), and cut the price in half. One other nitpick: the controller's built-in rechargeable battery isn't removable, which could spell trouble down the road. For its part, Sonos insists that the battery will last at least five years. But with no front panel controls on the ZonePlayers, the system will live or die by the controller's battery life. For instance, after we frequently used the remote for one day, its battery charge was nearly halfway depleted.

It's clear that Sonos spent a great deal of time trying to achieve the level of user friendliness that Apple is known for, because setup was a breeze. At least one ZonePlayer in your system must be plugged into an Ethernet port somewhere on your network (we connected it to a Belkin Powerline Ethernet adapter and it worked fine). Subsequent ZonePlayers (up to 32 can be linked) can wirelessly communicate via a secure peer-to-peer mesh network (dubbed SonosNet) that the ZonePlayer automatically sets up. Although it's disappointing that one ZonePlayer in every house must be tethered to an Ethernet cable (it won't interact with your existing wireless network unless you connect an Ethernet to wireless bridge), wirelessly connecting additional ZonePlayers is exceptionally easy. You simply press two buttons--no need to wade through the wireless networking configuration steps that can bog down the process of setting up competing digital media receivers. To get going, you can install a wizard on your PC or Mac (we tried both), which in turn guides you through a short setup process to build the ZP100's index of playable computer-based tracks. Even relative tech novices should be able to get the system up and running in a matter of minutes. If you're already using networked directories, you can even point the Sonos straight to them, without using the setup software.

Features

The most impressive aspect of the system is the fact that you have your entire music collection--and the ability to distribute it throughout your house--at your fingertips. The advantage of the controller is a big one: instead of having to squint at a small LCD on an audio receiver or use your TV to navigate tracks and settings, the screen is in your hand--and it's in color. Yeah, Crestron makes some pretty nifty remotes, but those are usually part of expensive high-end systems that have been put together by a home installer, who ran cables behind walls and built speakers into them--expensive, custom jobs that make Sonos's price tag seem like a downright bargain. All ZonePlayers in a system can also be controlled with the Sonos Desktop Controller computer software interface, and you can always purchase additional wireless controllers as well.

For our tests, we set up one ZonePlayer in our living room and one in our master bedroom. One ZonePlayer we connected to an A/V receiver that powered a set of NHT tower speakers; the other we tested connected directly to a few different loudspeaker sets and a powered subwoofer. You can choose to stream the same music in each zone (the music is synced) or stream different tunes in different rooms. To toggle between rooms, you simply hit the Zones button on the remote and select the room you want (Sonos offers dozens of room labels from which to choose).

You can opt for standard playback modes such as Shuffle, Repeat One, and Repeat All; choose to fire up playlists created by other applications such as iTunes and Windows Media Player; or listen to playlists you've created by using the Sonos software or the remote to save a song queue. Obviously, the more meticulously you've organized your music, with the correct ID3 tag information and the like, the better the user experience you'll have. Oh, and if you have album art in your database, it will be displayed on the remote when the song plays. Nice.

The Sonos system, which supports updates through firmware upgrades, currently plays MP3, WMA, AAC, and WAV files but does not support playback of secure or DRM-encrypted WMA and AAC files, including those bought from Napster and iTunes. That said, there is a work-around. You can connect your iPod or other portable MP3 player to any of your ZonePlayers via the analog audio-in jacks on the back of the unit and play secure files that way (from the remote it's easy to switch to the audio-in source in any room). The audio-in jacks also give you the flexibility to attach a CD player or even a satellite radio and stream music from them to any room you've Sonos-ified. That's pretty sweet.

Unfortunately, the Sonos system doesn't yet support Rhapsody, a premium ($9.95 a month), on-demand music streaming service. Sonos assures us that a free firmware upgrade will be released in March to add the feature, and we were encouraged by our brief hands-on demo of the beta version. To its credit, the system comes preconfigured to play nearly 90 free Internet radio stations and can be configured to play additional stations, as long as they're broadcast in the streaming MP3 format.

We suspect a lot of people will spend more time listening to music this way than actually listening to their hard drive's stored collections. It's also worth pointing out that you can connect a networked storage device, such as the Buffalo Link Station, directly to one of the ZonePlayers and stream music from it instead of the hard drive on your computer. In fact, this setup is ideal, because your computer doesn't have to be on for you to access to your music collection.

If we missed one thing, it was a digital-out connection. A digital audio receiver costing this much should allow you to connect digitally to an A/V receiver. The sound difference would be noticeable only to audiophiles, but anytime you can preserve an all-digital connection, it's preferable.

Performance

In general, the system is zippy, with little or no lag time when accessing music and switching from room to room. Click the Enter button at the center of the touch wheel, and a selected song typically plays within a fraction of a second. In fact, thanks to the circular ribbon controller that scrolls through track lists, the experience of using the Sonos remote is very similar to the experience of using an iPod to navigate and play your music--except that the Sonos's color screen is bigger and easier to read. On the other hand, it's a shame that the remote doesn't have page-up and page-down keys to facilitate skipping around in long track lists. In our tests, the remote only lost its wireless connection to SonosNet only once (Sonos says you can roam up to 150 feet from any ZonePlayer before a connection is lost) and restored itself quickly.

Sound quality was also pretty impressive. With the first ZonePlayer connected to our A/V receiver's analog line inputs, tracks such as Stevie Wonder's "Superstition" sounded multidimensional and clear. In an A/B listening test comparing the ZonePlayer and Roku's single-room SoundBridge, the ZonePlayer proved to have a brighter, more open sound with less bass emphasis than the Roku. Although we liked the ZonePlayer's off-the-shelf sound, basic bass and treble tweaks were easy enough to make with the remote.

The ZP100's robust, spring-loaded, wire binding posts inspired confidence when we directly connected the unit to speakers. The built-in 50-watt-per-channel amp did an admirable job of driving our bookshelf-size Event 20/20 studio monitors to loud volumes without noticeably straining. Although the amp couldn't make an old set of floor-standing Boston Acoustics A70 speakers play quite as loud, we were satisfied with the results. As long as your speakers are relatively efficient, they should perform well connected directly to the ZonePlayer. Connecting an active NHT M-00 subwoofer to the ZonePlayer's RCA type subwoofer output improved the overall listening experience by giving the system the same bass prowess as a serious home-theater rig. (Because the matching Sonos SP100 bookshelf speakers we received were nonfinal prototype units, we'll wait to test final production samples before commenting on their performance.)

The one area where we had a little concern is with the battery life of the remote. With light use, you should be able to go about a week without recharging, but we'd recommend buying the remote's optional $50 dock/charging cradle when it comes out later this year. That way, when you're not using the remote you can leave it in its dock, and it'll always have a full charge.