Build a Whole-home Audio System
Many of us here at Macworld are music lovers. We listen to a lot of music in a lot of places around the house. Which means many of us are also big fans of Sonos' Digital Music System, which lets you easily get your music into multiple rooms using a combination of hardware, software, and remote controllers. Some of us are also longtime fans of Logitech's Squeezebox product line, which similarly gives lets you pipe digital music all over your house.
But every time we write about Sonos or Squeezebox, a number of readers (understandably) ask, "Can't you do the same thing with a bunch of AirPort Express units and speakers using AirTunes?" (AirTunes is technology that allows you to play audio from iTunes on a remote audio system connected to an AirPort Express.) After all, the Sonos and Squeezebox systems are relatively expensive, so some people wonder why you would opt for either over a system based on Apple gear.
With that question in mind, we set out to see if we could put together a whole-house audio system, based on AirPort Express units, that can compete with Sonos- or Squeezebox-based setup. We weren't looking for the least-expensive setup: Sticking an AirPort Express and a set of inexpensive powered speakers in each room would work, but it wouldn't give you anything near the same functionality and audio quality. What we wanted was an Apple-based, whole-home audio system that approaches the audio quality and features of the Sonos and Squeezebox systems.
Here's a rundown of our experiences, along with some quick, back-of-the-envelope estimates of how much each system would cost. Note that these estimates assume you don't have the equipment necessary for each component of the system; in reality, you may already have some--or even all--of the equipment you need.
Unless you've got Ethernet wired throughout your house, the first thing you'll need to do for all three systems is set up a wireless network. In the case of an AirPort Express-based system, that means a standard Wi-Fi network, but it must be one hosted by an Apple-branded base station; third-party wireless access points don't support AirTunes.
Although you can use an AirPort Express as your main base station, we recommend an AirPort Extreme for the flexibility to connect devices via Ethernet and the capability to store media on a connected hard drive. Just as important, using an AirPort Express as the main base unit limits you to just 10 wireless devices--a limit you're likely to quickly reach given that the count includes iPhones, iPod touches, computers and laptops with wireless connections, and other AirPort Express units.
Logitech's Squeezebox players all work with both Ethernet and Wi-Fi base stations of any brand. Once again, we'd recommend you use a base station with support for a large number of connected devices, since they add up. But if you go for the Squeezebox line of players, you can choose any brand of wireless router, including Apple's AirPort.
The Sonos system, on the other hand, creates its own, proprietary wireless network. Advantages of this approach include easier setup and less interference. The Sonos network is also a mesh network, which means that instead of the network being hosted by a central base station, any device can extend the network to any other device, giving the system better overall range and performance.
But the Sonos system still needs to connect to an existing network (with Internet access) somewhere. Which means at least one Sonos component must be within wired distance of either your router (whatever type of router it is) or an Ethernet port. If your router or network port is in a closet or a room where you won't be listening to music, the $99 ZoneBridge is a compact (4.3-inches square, 1.6 inches tall) box that connects to your wired network and acts as the first node in the Sonos wireless network. If you do plan to listen to music in the room with your network port, both the $349 ZonePlayer 90 (ZP90) and the $499 ZonePlayer 120 (ZP120), each described below, incorporate the ZoneBridge's functionality.
Cost if you don't have equipment: Apple: $179 (AirPort Extreme); Squeezebox: $30 and up (cost of a Wi-Fi router if you don't already own one); Sonos: $99 (ZoneBridge), $349 (ZP90), or $499 (ZP120) plus router.
Host your music
In order to set up a music system based on digital media, you need somewhere to host that media. The Sonos and Squeezebox systems are more flexible here: while both can access music stored in your iTunes Library, they can also use music stored on a network drive. For example, the Sonos can connect to music on a Time Capsule, a USB hard drive connected to an AirPort Extreme base station, or an Ethernet-equipped NAS drive connected to your network.
To go the Apple route, you need a computer running iTunes. (The computer also handles the actual playback; with the Sonos and Squeezebox systems, each ZonePlayer handles playback independently.) This can be an old Mac or PC you aren't using anymore, your current Mac, or a new Mac or PC you purchase specifically for this purpose. Each option has its drawbacks: Using an older Mac may require you to upgrade the hard drive to hold all your media, performance may be poor, and older computers use considerably more electricity that today's models. Using your current Mac means that you have to share iTunes with anyone else in the house who wants to listen to music. And a new Mac will cost you a good chunk of change.
The Squeezebox system gives you a couple options. Though it requires you to run Squeezebox Server software, you can run that server on either a computer or a compatible NAS. If you go the NAS route, Logitech officially supports only the Netgear ReadyNAS, though many other NAS devices are also compatible. For the computer-based approach, you can use any recent Mac, Windows, or Linux PC.
(Of course, even if you go the NAS route for the Sonos or Squeezebox system, you'll still need a computer with an optical drive if you want to rip CDs to add their contents to your digital music library.)
We used a 2009 Mac mini for the AirTunes system. The Mac mini is ideal for this type of situation, as it's tiny, has plenty of memory and horsepower for handling iTunes and related tasks, runs cool, and--perhaps best of all--uses much less energy than most computers, both when running and while asleep. It also supports Wake on Demand (see "Take control," below). The Squeezebox system also used a Mac mini.
Cost if you don't have equipment: Apple: $599 for Mac mini, or the price of a used Mac; Squeezebox: ~$250 for compatible NAS drive, or an inexpensive or used computer; Sonos: ~$100 and up for a NAS drive.
Choose your rooms
The next step is getting your music into your rooms. All three systems let you send audio to your choice of locations, using hardware in each room to receive the wireless transmission and convert it to a signal you can feed to a stereo or a set of speakers. With the Apple system, that hardware is a $99 AirPort Express unit. Once the Express is set up (see the next section), any audio you send from iTunes to that Express is pumped out the Express' analog/optical-digital audio-output minijack.
It's worth noting that if you've already got an Apple TV in a room, you can use the Apple TV for AirTunes instead of an AirPort Express. The Apple TV shows up in iTunes as a destination for audio, just as an AirPort Express would.
The heritage of the Squeezebox product line is in devices that can be placed in a standard stereo rack. As a result, most Squeezebox products have some sort of display on their front and offer support for an infrared remote control. The $300 Squeezebox Touch, the "standard" model, is a compact box that, like the AirPort Express, connects to an amplifier or powered speakers. But the Squeezebox offers left/right RCA jacks for analog audio, as well as both coaxial and optical jacks for a digital signal. It's also got a bright, 4.3-inch color touchscreen display on the front that shows album art, track information, and even the time and weather; you can also use the touchscreen to control playback without a remote.
Alternatively, Logitech offers a slew of other options: the $150 Receiver, a bare-bones unit that inexplicably requires the $300 Controller, covered later, to set up; the $400 Duet, a bundle featuring both the Receiver and Controller; as well as two models that include speakers (covered later in "Amp it up").
With the Sonos system, each listening room needs a ZonePlayer. The $349 ZonePlayer 90 (ZP90) is a compact box, approximately 5.5 inches square by 2.9 inches tall. Like the Squeezebox, the ZP90 can connect to stereo or powered speakers via analog or digital jacks. The ZP90 doesn't have any sort of display, but it does provides hardware buttons on the front for adjusting and muting the volume.
The $499 ZonePlayer 120 (ZP120) is essentially a ZonePlayer 90 with a built-in 55-Watt-per-channel, Class-D amplifier. Designed for rooms that don't have an existing stereo system, the ZP120 gives you everything you need except the speakers; speaker terminals on the back of the unit let you connect, using standard speaker cables, whatever speakers you decide on. The ZP120 also provides a subwoofer output for connecting a powered subwoofer.
Both ZonePlayers have a couple additional tricks up their virtual sleeves: First, each also sports left/right RCA inputs; connect any audio source--a CD player, an iPod, a TV--to these inputs and you can send that device's audio to the other ZonePlayers, making it easy to listen, for example, to the audio track from a televised sports event anywhere in the house. (You can even choose how that audio is encoded for transmission.) Second, each ZonePlayer provides a two-port Ethernet switch for connecting wired devices--TiVo, game console, computer, NAS drive--to your network.
(Logitech and Sonos also sell all-in-one units that combine a Squeezebox or ZonePlayer, respectively, with an amplifier and speakers; more on that in "Amp it up.")
Cost if you don't have equipment: Apple: $99 (Express) or $229 (Apple TV) for each room; Squeezebox: $300 for each room; Sonos: $349 (ZP90) or $499 (ZP120) for each room.
Set up your "zones"
While each system requires a bit of initial setup on your computer, the procedures for adding new rooms to your system differ notably. With the AirPort Express-based system, you need to configure each remote AirPort Express unit--using a computer running AirPort Utility--to join your network and act as a remote music device for iTunes. While the software walks you through the steps to set up the device, you have to make a series of decisions that require a certain level of comfort with technology.
To set up a Squeezebox Touch, you plug it in and, using the touchscreen, select either Ethernet or wireless. For wireless, you then select your Wi-Fi network and enter the password. The Squeezebox Server software automatically detects the new Squeezebox and adds it to its menus.
Setting up a remote ZonePlayer is as simple as choosing the Add A Zone command (on your remote or in the Sonos Controller app on your computer) and then pressing a button on the new ZonePlayer; the new zone is automatically added and configured.
All three systems, Apple, Logitech, and Sonos, provide computer software for controlling playback, choosing which rooms get music, and setting up playlists--iTunes, the Web-based Squeezebox Server, and the Sonos Controller, respectively. But while this software is convenient when you're sitting at your Mac, it's not nearly so when you're in another part of the house and want to enjoy some tunes. So all three companies provide solutions for remote control.
For the Apple system, that solution is Apple's free Remote app for the iPhone or iPod touch. Once you've completed the one-time pairing procedure between the app (on your i-device) and iTunes (on your Mac), launching the app causes it to automatically connect to iTunes--a process that generally takes five to ten seconds. The app gives you an impressive amount of control over playback: You can browse playlists, artists, albums, genres, podcasts, and more; you can search for particular items; you can use the Genius feature; you can even create and edit playlists, all from your iPhone or iPod touch.
For the Logitech system, you'll similarly get the best multi-room control using your iPhone or iPod touch. However, strangely, Logitech doesn't supply an official app to do the trick. Instead, there are two third-party remote apps, the best of which is Penguin Loves Music's $10 iPeng. iPeng looks similar to Apple's Remote app, but with support for the additional features of the Squeezebox.
Logitech also offers a dedicated hardware remote, the $300 Squeezebox Controller, that includes a small, color screen and a faux Click Wheel controller. However, we aren't fans of this remote--you'd be far better off buying a $200 iPod touch and one of the Squeezebox-remote apps. Unfortunately, as mentioned above, the Squeezebox Controller is currently the only way to set up the $150 Receiver.
(Note that the Squeezebox Boom includes an infrared remote, but it's limited to letting you navigate the device's on-screen menus. It's useful for controlling the Boom itself, but not conducive to controlling a multi-room system. Also, the Squeezebox units--except the Receiver--each provide some degree of playback control on the unit itself; if you're listening in only one room, this allows you to control that room's audio without a remote.)
Like Apple, Sonos provides a free app for the iPhone or iPod touch, Sonos Controller for iPhone, which we covered earlier this year. The interface for this app is strikingly similar to that of Apple's Remote app, which is a good thing. Like the Apple version, Sonos' iPhone app gives you complete control over playback, although it also provides access to Internet services supported by the Sonos system but not by the Apple system--Rhapsody, Napster, Sirius, Pandora, and Last.fm--and it lets you browse Internet radio right from the remote.
Sonos also offers a dedicated hardware controller, the $349 Sonos Controller 200 (CR200). The CR200's interface is very similar to that of the company's iPhone app, but the CR200 offers better performance, dedicated hardware buttons for frequently used functions, much better battery life (up to 5 days), and a move-to-wake motion sensor. As our colleague Christopher Breen pointed out in his review, the dedicated controller is also less complicated as a "family remote"--you pick it up and it's ready to go; with an iPod touch or iPhone, you've got to wade through your other apps--or perhaps quit an app you're currently using--to launch the Sonos app. Finally, the CR200 comes with a charging cradle.r--
(On the other hand, one advantage of using an iPod touch-based controller is the bevy of accessories available. For example, as part of a recent renovation, one of us installed in-ceiling speakers in our master bathroom. By sticking an iPod touch inside an OtterBox Armor case, he can control his tunes while relaxing in the whirlpool tub and not worry about the iPod getting wet--or even submerged. Yes, this falls under the category of "first-world problems.")
Whichever system you have, if you choose to go the iPhone-app route for your remote, we recommend dedicating an iPod touch for the purpose. While it may be less expensive to use your current iPhone or iPod touch, unless you're the only person who ever controls audio and you always have that device handy, it's inconvenient to share a single remote between your audio system and the myriad other things your iPhone and iPod touch are used for throughout the day. Not to mention that using your only iPhone or iPod touch as the remote for your audio system means you'll eventually be caught with a dead battery when you desperately need that device for some other use.
Cost if you don't have equipment: Apple: $199 (iPod touch); Logitech $199 (iPod touch) or $300 (Squeezebox Controller); Sonos: $199 (iPod touch) or $349 (CR200).
There's one more thing related to remote control to consider: waking up your system. The Sonos system's components automatically sleep when not being used in order to conserve energy. However, they continue to watch the Sonos-created network for activity; if a ZonePlayer detects a command meant for it, it automatically wakes up.
An Apple-based system (or a Sonos or Logitech system accessing content stored on a computer) requires a computer, and unless you want to waste electricity by keeping that computer on and awake 24/7, you'll want to configure it to sleep when not in use. The challenge here is how to wake it up from across the house when you want to listen to music. As long as your Mac is connected to your network via Ethernet, or you have a recent Mac that supports Wake on Demand, you can use a technology called Wake on LAN to wake the sleeping computer over the network. The Squeezebox will automatically wake the computer that Squeezebox Server is running on. For the Apple-based system, if you're using an iPhone or iPod touch, the tool I chose is Wake on Oui, an iPhone app that, once set up, lets you tap a button to wake your Mac.
Cost if you don't have equipment: Apple: $1 (Wake on Oui); Squeezebox: $0; Sonos: $0.
Amp it up
Once you've got your system set up to send music to various locations, you need to get that music signal into an audio system that lets you listen to it. If you've already got a stereo in a room, you can simply use that, running the appropriate audio cable from an audio output on the AirPort Express, Squeezebox, or Sonos ZP90 to your receiver or amplifier.
If you don't already have an audio system in a room, you've got a few options. For the AirPort Express, Squeezebox, and Sonos ZP90, the simplest and least expensive solution is to connect your player hardware to a set of self-powered computer speakers. Unfortunately, with a few exceptions, the sound quality won't compare to what you can get with a good set of traditional speakers and a good amplifier.
(One of those exceptions is Audioengine's $349 Audioengine 5--aka, A5--a standout powered bookshelf speaker system that provides excellent sound quality in an attractive, compact package. What makes the A5 especially appealing for this use is that the rear of one of the A5's two speakers has an AC outlet specifically designed for an add-on device such as AirPort Express, Squeezebox, Sonos ZP90--you just plug in your wireless unit, run a short cable from its audio jack to the A5's audio input, and you're good to go.)
The second option is an all-in-one unit that combines a wireless receiver with an amplifier and speakers. Logitech makes two such Squeezebox models. The $200 Squeezebox Radio is designed for your nightstand; it's got a single mono speaker that offers decent quality and volume, but isn't really capable of cranking the tunes. The $300 Squeezebox Boom has a larger, boom-box shape (though it'll still fit on a nightstand or shelf), with stereo speakers and more power for better audio quality. The Boom also provides a connection for a powered subwoofer to really get the party going. Neither model is going to offer the audio quality of a dedicated set of speakers and an amplifier, but they're affordable, and we liked the sound of the Boom. Both models also come with front-panel displays and controls, so you can operate them without a remote (though the Boom does include a small, infrared remote).
Sonos, on the other hand, is a newcomer to this space. The company just announced the $399 $ZonePlayer S5, which is essentially a ZP90 with an amplifier and five speakers in a desktop enclosure. We suspect the S5 will sound noticeably better than the Logitech systems, albeit at a higher price and with no built-in display and few controls.
Still, there's no doubt that for the best sound quality, you'll want a dedicated amplifier and a good set of speakers. Once you go this route, the choice of speakers is up to you--you can use your favorites with any system. For smaller rooms, we recommend a good set of bookshelf models, such as the $250/pair Paradigm Atom v.5 and $279/pair PSB Alpha B1 speakers we covered in our article on building an iPod stereo system. Another good option we've been testing lately is the Audioengine P4 (AP4; $249/pair), the unpowered--and slightly smaller--sibling of the A5 I mentioned above. Alternatively, you can go all-out with a set of larger speakers, or a sub/sat system, that offer full-range audio.
If you go this route, the Sonos ZP120 offers something that the Squeezebox line doesn't: a ZonePlayer with its own amplifier, so all you need to add are a pair of good speakers. If you're a music fan, you may have such a pair already attached to an old stereo. For only $150 more than the ZP90, you get a very good amp that has plenty of juice to fill a good-size room.
For the Apple-based system and the speaker-less Squeezebox units, the choice isn't as simple, as you've got to shop for a quality amplifier among the myriad choices out there. For the fun of it--and to nail down some kind of price estimate--we decided to find a great multi-room-system amp. We narrowed down our search with a couple criteria: We tried to put together a system that competed with the Sonos ZP120 in terms of features and quality, so we wanted an amplifier that was small in size while providing plenty of power, and we wanted an amplifier that was energy efficient. (The Sonos ZonePlayers sleep when not in use to conserve electricity.)
What we settled on was the $349 Parasound Zamp v.3, a compact, 45-Watt-per channel integrated amplifier specifically designed for systems like these; Dan Frakes tested two Zamps. At only 9.5 inches wide, 10 inches deep, and less than 2 inches high, each Zamp is tiny as traditional amplifiers go, but it's built like a tank--it's largely made of metal, weighs seven pounds, and comes with a 10-year warranty--sounds great, and puts out plenty of power, handling the big NHT Classic Four towers in Dan's main stereo rig surprisingly well.
Because it's made for custom audio installations, the Zamp has a number of features that make it perfect for pairing with an AirPort Express or Squeezebox. It automatically goes into a power-saving sleep mode when no audio signal is present, and automatically wakes up as soon as it detects a signal. In other words, the amplifier is on only when you're sending audio to its AirPort Express unit. With a traditional amplifier, to send music to the family room, you need to either go to the family room and turn on your audio system--a task that sounds simple, but gets annoying very quickly--or you need to leave it on all the time, wasting electricity. The Zamp also has a convenient rear-mounted set-it-and-forget-it volume dial; once you've matched the volumes in your various rooms, you can use your AirTunes or Squeezebox volume controls.
Thanks to its small size and heat-protection features, the Zamp also, like the ZP120, works well if you've got speakers built into walls or ceilings. The cables for Dan's in-ceiling speakers lead to a "media closet" that also hosted the Mac mini he was using as the center of the Apple-based system for this article. Two Zamp units sat next to the Mac mini, an AirPort Extreme, two AirPort Express units, and an external hard drive for the mini, and the closet never got noticeably warm. In short, Dan loved the Zamp, and found it to be comparable to, if not better than, the amplifier inside the Sonos ZP120 in terms of audio and build quality.
Cost if you don't have equipment: Apple: cost of amplifier and speakers for each room; Logitech: cost of amp and speakers for each room, or $300 for Squeezebox Boom for smaller rooms or $200 for Squeezebox Radio for the nightstand; Sonos: cost of amp and speakers for each room (with the ZP90), just speakers for each room (ZP120), or $399 for an S5.
For the purposes of real-world testing, the whole-home audio system Dan put together consisted of five rooms of audio. Two of them paired an AirPort Express or Apple TV with an existing stereo system, two paired an AirPort Express with a Zamp and speakers, and one paired an AirPort Express with a set of Audioengine A5 speakers. Dan used this Apple-based system for a little over a month to see how it compared to the Sonos system. Jason, on the other hand, tried out a Squeezebox-based system that covers three rooms of his house, one with a Squeezebox Boom, one with a Squeezebox Radio, and another with an older Squeezebox Classic player attached to a Sony amplifier and speakers.
If you use your multi-room audio system frequently, one of the best features of the Sonos system is the concept of Zones. You can send different audio to different rooms, as well as separately control the volume level in each room. In practice, this means you've essentially got a separate audio system in each room, all controlled from a single remote, but you still have the option to link all rooms to play the same music together. Even better, you can easily link particular rooms at any time; for example, you can play one playlist in the kitchen and family room, while another plays in the bedrooms, and still another plays outside on the patio. (Within groups, you can control each zone's volume separately; once you get the right balance, you can then adjust the overall level with one slider.)
There's no denying that Sonos excels when it comes to multi-room audio, but Squeezebox has also supported the concept for quite some time. Each Squeezebox player can play different music, or multiple players can be synchronized with one another to supply the same music throughout your house. Although Squeezebox's approach isn't as elegant as Sonos's, it does the job, allowing party guests to move from room to room while hearing the same carefully constructed iTunes playlist. And if you're using the iPeng iPhone app, the Squeezebox system's multi-room control approaches that of the Sonos.
The AirPort Express setup, on the other hand, supports only a single audio signal, so while you can choose which rooms get audio at a given time, all rooms must listen to the same thing. And unlike the Sonos system, you have only a single, master volume level for all rooms: crank the volume and it increases the same amount in every room. This means that unless you have the same audio system in every room, your initial amplifier setup will include some manual gain staging--separately adjusting each room's volume level, walking back and forth between rooms many times, to match.
Beyond multi-room support, the Sonos system and Squeezebox line also have a number of other advantages over the Apple-only system. They support more formats than iTunes (including WMA, FLAC, and Ogg Vorbis); let you browse and play Internet radio stations; and include sleep and wake functions. But for many people, perhaps the biggest advantage for the Sonos and Squeezebox systems is their built-in support for a slew of music services--Rhapsody, Napster, Sirius, Pandora, and Last.fm among them.
Sonos has a couple unique advantages, too: the capability to stream a separate audio source (a CD player or TV) from one room to all the others; and the mesh network, which, because it creates its own wireless network, avoids potential connection issues from having a firewall running on your computer (a common source of problems with an AirPort Express-based system).
On the other hand, the Apple-based system isn't without its own advantages. The most obvious is that many users, especially Mac users, already have at least some of the required equipment, making this approach considerably cheaper than purchasing a Sonos or Squeezebox system. Similarly, if you're already an iTunes user, the AirTunes system will be instantly familiar; both Sonos and Squeezebox offer queue-based interfaces that can be a bit confusing to those weaned on iTunes. (Once you get used to them, however, you may be frustrated that iTunes doesn't offer a similar feature.)
Since the Apple system is controlled directly from iTunes, it's also superbly integrated with iTunes features (such as Genius) and iTunes playlists (including smart playlists). The Squeezebox system automatically loads your iTunes library and playlists, but it doesn't currently support other features such as Genius and iTunes DJ. The Sonos system can import iTunes playlists, but the feature is a bit kludgy, and you need to re-import playlists each time you modify them in iTunes.
The AirTunes system also supports iTunes-DRM music; Sonos and Squeezebox gear can't play it. And adding music to your system is a bit easier with the AirTunes system. You just rip CDs or drag audio files into iTunes; that music is immediately available for playback. If you've set up any Smart Playlists in iTunes that would include that new music, those playlists are similarly updated automatically. Adding music to the Squeezebox and Sonos system involves a bit of a delay: whenever you add music to iTunes or to a separate music directory on your hard drive or NAS, the Squeezebox and Sonos systems must re-index your music library in order to recognize that new music.
On a non-musical note (pun intended), a side benefit of a system based on AirPort Express units is that you can connect a USB printer to any Express to make it available to any computers on your local network.
Finally, it's worth noting that there are workarounds for AirTunes that, while imperfect, approximate a few of the Sonos and Squeezebox system's features. If you have software on your Mac that provides access to one of those online music services, you can use the Mac software Airfoil to stream that audio across your AirTunes system. (Although the Sonos and Squeezebox systems accesses a higher-quality Rhapsody stream than the browser version, and the Sonos Pandora subscription doesn't have commercials.) While you can't browse Internet radio stations from Apple's Remote app on your iPhone or iPod touch, if you have particular Internet radio stations you listen to frequently, you can add them to a playlist; you can browse that playlist, and start playback of any Internet radio station, from the iPhone app.
The total cost
When starting this experiment, we had hoped to end up with a table comparing the costs of each system. But as you can see from our cost estimates throughout the article, there are so many factors that affect how much you'll have to spend, even if you're starting from scratch, that a nice, neat table wasn't in the cards. Instead, here's as simple a cost summary as we could put together:
If you're starting from scratch, the initial cost of the AirTunes system is approximately $978: $179 for an AirPort Extreme, $599 for an entry-level Mac mini, and $200 for an iPod touch with the Wake on Oui app. The per-room cost is $99 (an AirPort Express) plus the cost of an amplifier and speakers.
Estimating the cost of a Sonos system is a bit more complicated. The initial cost is anywhere from $398 (a ZoneBridge, a NAS drive, and an iPod touch with Sonos app) to $948 (a ZonePlayer 120, a NAS drive, and the Sonos Controller 200), depending on your choice of controller and whether or not you plan to listen in the room that serves as the "base" of the system. The per-room cost is either $349 (a ZP90) plus the cost of an amplifier and speakers, or $499 (a ZP120) plus the cost of speakers. (Note that Sonos does offer discounted bundles; for example, if you purchase a ZP120, ZP90, and CR200 together, you save $200.)
For the Squeezebox, the initial cost is $250 for a NAS drive or $599 for a Mac mini, and then $200 to $400 per room, plus the cost of an amplifier and speakers for rooms not serviceable by a Squeezebox Boom or Squeezebox Radio. The Squeezebox's on-device controls reduce the need to buy a dedicated $199 iPod touch-based remote if you tend to listen in individual rooms, though for true, whole-house control, you'll still want one.
In the end, we suspect that for most people, even those starting from scratch, the Apple system is going to be the least expensive; how much less expensive can vary wildly depending on your setup and current equipment.
With all that information in mind--and there's admittedly quite a bit of it to absorb--which route should you take to get your tunes everywhere?
For those who've already got a good amount of the necessary Apple hardware, especially an AirPort Extreme and several AirPort Express units, an AirTunes system is appealing thanks to the much lower cost of entry. (And, in fact, if you have enough of the required gear already, you can start by "test driving" the AirTunes system in just a couple rooms to see if you like it.)
If you're starting from scratch, or mostly from scratch, however, it's worth taking a step back to consider which system might be the better choice for you.
If you think you'll spend most of your time listening in only one room at a time, or listening to the same music in all rooms, and if most of the music you'd want to listen to is already in iTunes, an AirPort Express-based whole-home system will likely suffice, and it will do much of what you need for a lower price.
On the other hand, if you want more flexibility, including the capability to listen to different audio in different rooms, and the option to take advantage of subscription and online services, either the Sonos system or Squeezebox line may be worth the extra money, especially when you consider their ease of use and other benefits.
In terms of choosing between Sonos and Squeezebox, it once again come downs to details. The Sonos system is more expensive overall, but it offers a more elegant experience, its mesh network makes it much more reliable in larger houses (especially those not already permeated by reliable Wi-Fi), and the ZP120 with integrated amplifier is perfect if you've already got a good set of stereo speakers. The new S5 also looks to be a great way to get big, high-quality audio into rooms that don't need a full-blown stereo system.
Logitech's Squeezebox line is less expensive and provides multi-room capabilities that are nearly as good as Sonos's, but it relies on your house's own Ethernet and Wi-Fi networks. If you've got a limited number of rooms that you really need to fill with expansive, high-quality sound (via a Squeezebox, amplifier, and external speakers), but several smaller rooms that could be served well by the integrated speakers in the Squeezebox Boom or Squeezebox Radio, Squeezebox may be a better deal.
Whatever approach you take, one thing's for sure: once you've experienced being able to listen to your favorite music wherever you are in the house with a few taps on a screen, you'll wonder how you ever got along without your whole-house system.