Whole-House Music Systems a.k.a. Multi-Room Music Systems

part of materialism by Philip Greenspun; written in October 2005, revised November 2012

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In setting up a system to play music in multiple rooms throughout a house, start by answering the following questions: [If you're pressed for time and just want to buy something, the author's current recommendation for most applications is the Sonos system (see below), pulling music from a Synology disk array or Western Digital My Book Live, and driving B&W speakers.]

Ridiculously Simple Solution to the Whole-House Music Challenge

Get a $30 FM transmitter and connect it to your primary music source. Tune in the signal on FM radios elsewhere in your house.

Wireless Speakers

Get a pair of Acoustic Research wireless speakers, plug the transmitter into your primary music source, carry the speakers into the room where you want to listen. If you get enough of these, or have a small house, call this a "whole-house music system."

Whole-House Music Approach I: Add Extra Speakers to Legacy Stereo

The simplest possible approach to multi-room sound is adding a second pair of speakers to an existing home stereo system (the "legacy stereo"). You pay an electrician to run speaker wire in the walls and either terminate them in a second room or terminate them at in-wall speakers. The typical A/V receiver will have a second pair of speaker outputs and can drive a small additional pair of speakers without any challenge. You need to make sure that the cable is UL-rated but otherwise there is no trick to the wiring.

Problems with this approach include the following: (1) might not be able to control the volume of the rooms independently, (2) cannot control the volume from the second room, and (3) cannot control the source, pause, or move forward a track from the second room.

The classical solution to the volume control problem is to place an "LPAD" resistive voltage divider in the second room, which tends to look like a volume control knob on the wall. The LPAD converts a selectable amount of unwanted power amplifier energy into heat. LPADs compromise sound quality to some extent.

On the assumption that the legacy stereo is controlled via infrared (IR) remote controls there are various techniques for getting IR signals back into the room where the CD player and receiver reside. One technique is the wall keypad connected (more wiring) to an IR transmitter near the legacy stereo. This has to be programmed so that pressing the "track forward" key on the wall keypad will send out a "Pioneer CD player track forward" IR signal. If you're willing to carry remotes physically around the house you can get wireless IR repeaters or "extenders" that listen for IR signals in one room and rebroadcast them in the room with the legacy stereo.

Now you're set up but what if you want to add a third or fourth room? This will probably be beyond the capabilities of the legacy stereo power amp.

Whole-House Music Approach II: Add a Multi-Room Power Amp and Control System to Legacy Stereo

Various companies make multi-channel amplifiers specifically designed for whole-house music. You plug your legacy stereo components into the multi-room amp and then run a bundle of wires from the multi-room amp out to each room. Each room has an in-wall speaker that takes a musical signal from the speaker wires in the bundle. Each room has a wall-mounted keypad and volume control that sends control signals back to the multi-room amp. The control signals tell the central amp to "reduce volume to the bathroom speakers" or "junior is in his bedroom and doesn't want to listen to NPR so change the source for this room from FM tuner to the CD jukebox" or "the Forward button was pushed; send an IR signal to the CD player asking for the next track".

These systems represent the state-of-the-art circa 1990 and work pretty well if the legacy stereo is where your content lives. In a McMansion the sound quality might be compromised to some extent by the long speaker wire runs. In a rental apartment you might not want to pay for all the hard-wiring that is entailed. Without a good interface among the components it would generally be impossible to see, on a keypad, the name of the CD being played or the freqency of the tuned-in radio station. Otherwise this is a reasonable way to go.

The best example of this kind of system ever designed is the B&W CASA system. They run a single CAT5 wire (computer Ethernet cable) from the central brain to each in-wall loudspeaker. The CAT5 wire carries a balanced analog signal, low-voltage DC power, and digital control signals back to the brain. Each speaker has its own low-voltage DC power amplifier, like the amps found in car stereos (it would be against electrical code to mount a mains-voltage AC amplifier in the wall). Each speaker has an IR diode watching for remote control signals, which it will repeat back to the brain, which is presumably adjacent to the legacy stereo. Thus you can walk around the house with your, say, Pioneer remote control and point it at any in-wall speaker and have it work just as though you were in your living room. I said to myself "this system seems just about perfect, though it would sure be ugly if B&W decided to discontinue it and left you with a house full of orphaned in-wall components that only understand this proprietary CAT5 interface." Back in the early 2000s, while I was debating whether or not to install one, B&W discontinued CASA. This is a good example of why one needs to think long-term before cutting holes in walls.

Whole-House Music Approach III: Think Digital

In a world where content is increasingly digitized and sitting on a computer hard drive, how can it make sense to place the legacy stereo at the center of the house? The legacy stereo offers high quality reproduction for critical listening but otherwise has little to recommend it. The home computer system has access to millions of songs on subscription-based services such as Rhapsody and Yahoo! Music. The home computer system contains MP3 files, podcasts, and videos. The home computer system knows the names of the songs that it is playing and often even can show you a nice photo of the album cover. The home computer system is part of a high-speed wired and wireless network.

One you place the home computer at the center of the house, the whole-house music system looks completely different. Any computer or computerized device that can talk to the home computer can play any music file in your collection. The design challenge becomes one of user interface and software. How do you let someone who is not at the computer browse through a huge collection of files? How do you make sure that the digitally networked machines throughout the house are playing the same song?

The rest of this article will be about building a modern computer-centric whole-house music system.

Think Digital, Step 1: Take the PC Out of the Critical Path

There are a lot of good things about the personal computer but sometimes they need to be rebooted or replaced. If you're editing video or high-resolution digital photographs the PC's processor may become saturated. A high-quality whole-house music system will continue to play even if the PC has been shut down. What you want is a file server.

You could get a small PC with no monitor to function as the file server and control it remotely from your desktop PC. A better solution, however, is network-attached storage (NAS). The NAS box is a compact little machine that has enough electronics to talk to hard drives and the network. The NAS box has no audio, video, or keyboard interfaces. The NAS box has no CD or DVD drives. The NAS box may have a sophisticated RAID ("redundant array of independent disks") controller so that the failure of a single disk drive will not result in any loss of data or interruption in service.

Based on chassis noise and ease of setup, the best current NAS devices for the home are the Synology disk array and Western Digital My Book Live. Make sure to get something like a Netgear Gigabit Ethernet switch so that computer-to-computer file transfers are fast. Also, my experience with routers is that Netgear are the most reliable. A Sonos system attached to a Linksys router, for example, would periodically dissociate all of the zones. When the Linksys was replaced by a Netgear device, the problem never recurred.

How big a disk subsystem do you need? One hour of music on an uncompressed CD occupies 635 MB of space and therefore you could fit 1000 hours onto a 1 TB RAID 5. With a lossless compression format such as FLAC you could double this to 2000 hours. Most people receive and/or store their music CD in formats such as MP3 that are much more space-efficient. An hour of music at 192 Kbps takes up only 86 MB, which means that a 1 TB NAS box could store nearly 7300 hours. Except for CDs that you rip yourself, most music comes in at a lower sampling rate. Until 2009, Apple managed to get consumers to shell out $1 each for tracks that were recorded at a middling 128 Kbps and wouldn't play on most devices due to Apple's refusal license its digital rights management scheme (in 2009, Apple finally decided to improve the quality to 256 Kbps and remove the DRM from some tracks). The FCC's new improved version of terrestrial radio is 96 Kbps. XM and Sirius satellite radio deliver music at 64 Kbps.

As of early 2009, the 750 GB size is probably the best choice for most people. It is large enough to store all the music within a household, several years worth of digital photography, and also hold backups for files on the various PCs in the house. If you are serious about archiving video, you will need substantially more disk space. A good solution is to purchase a four-slot disk array populated with only two disks. After a year or two, you'll have filled up the first two drives and can add two more. Two years from now, much larger disk drives will be available and therefore you will probably quadruple your storage capacity by adding two more disks.

Microsoft Windows Media Center and Windows Media Player

Included in the Home Premium version of Windows 7, Windows Media Center enables you to drive a Windows-based PC from a HDTV and then using Windows Media Center Extenders, drive other rooms within the house. Unfortunately, Microsoft doesn't seem to be able to explain how this works and there are not too many devices that comply with the protocol. Linksys makes some that cost $200, but they are really more designed for streaming video than for the simpler problem of streaming audio.

A simpler solution is Windows Media Player, which can stream hard-drive based music to "digital media players" that start at about $50. Microsoft is obsessed with flexibility and video, so they simply don't or can't explain how to use Windows Media Player to push audio to multiple rooms simultaneously and keep the music in sync. Probably it can be done, but nobody seems to know how and speaker manufacturers do not seem to be lining up behind Microsoft's standards the way that they do with Apple AirPlay (see below).

Apple iTunes/iPhone/iPod

For people who are content to stay within the Apple/iTunes world and who don't have a lot of rooms or need multiple zones, Apple and companies making AirPlay-compatible systems offer some simple solutions.

If all of your content is on a hard drive on a personal computer (Mac or Windows), plug in a AirPort Express with Airtunes (about $100). This has a line-level audio output jack that can be connected to a legacy stereo or a pair of powered loudspeakers. When running iTunes on your Windows machine or Macintosh the AirPort will repeat whatever is playing on the personal computer. A Keyspan IR remote control ($50) will let you skip tracks, pause the music, crank the volume up and down.

Problems with this approach include the following:

If you are starting from scratch, it is probably better to get AirPlay-compatible speakers. The audiophile choice among AirPlay devices is the B&W Zeppelin. With a single Zeppelin, you can plug an iPhone or iPod into the dock and play music in a straightforward manner. With a little more effort, you can hook up a maximum of three Zeppelins and drive them all from a computer or from an iOS device such as an iPhone or iPad.

Squeezebox

Logitech acquired Slim Devices, which makes a small "set-top box" with infrared remote control called the "Squeezebox" that sells for around $250. Unlike the Airport Express, the Squeezebox has a big display to show you what is playing and, together with the remote, it allows you to select what you want to hear using an iPod/Creative like menu structure. The Squeezebox has line-level analog output for use with a traditional stereo system or powered loudspeakers and digital outputs for use with a modern digital A/V receiver or audiophile digital-to-analog converter. The Squeezebox system provides for synchronization of multiple players so that the same music is heard throughout the house.

The Squeezebox has the ability to accept a USB drive or SD card and then stream the contents to additional Squeezeboxes. Supposedly the overall system is not as easy to set up and keep in sync as the Sonos.

You can look at current Squeezebox products at amazon.com. Under Logitech's management, the emphasis seems to have shifted to tabletop radios and away from full audio systems.

Philips Streamium

Among the large consumer electronics companies, only Philips has a series of product designed to distribute digital music through a house: www.streamium.philips.com. These suffer from a combination of the shortcomings afflicting the Microsoft and Apple systems mentioned above. Either a box has no power amplifier or it has no interface to legacy sources or it requires a huge TV. Philips introduced the system back in 2008 with great fanfare and then more or less abandoned it.

Sonos

Sonos is a good illustration of why we still need small companies (company Web site; amazon.com). Microsoft has built the Soviet locomotive of digital music systems. Apple assumes that all of the world's music is in iTunes and then pats itself on the back for adding cute design to the MP3 jukebox that was invented by others. Philips gives you an all-in-one "wireless music center" with its own 40 GB hard drive. It is very clear that Sonos worked the problem backwards from the consumer's point of view. Sonos seems to have assumed the following: Each Sonos "Zone Player" is a little white brick that can talk to the computers in the house, can talk to other Zone Players, and can talk to a fancy Sonos remote control. These communications capabilities enable the Zone Player to show you, via the display on the remote, what music is available to play and, depending how you've set it up, to tell other Zone Players to play the same thing. Each Zone Player has line inputs and outputs so it can take a signal from a legacy stereo or a television and pump it into the network at CD quality for other Zone Players to play. Each Zone Player has a 55 watt/channel power amp that enables it to drive one or two pairs of conventional loudspeakers. The Zone Player presents a clean appearance with only one light and three buttons: volume up, volume down, mute.

The basic setup for a 3BR apartment would be as follows. You would have one Zone Player next to the legacy stereo, connected via the line inputs, so that you could play MP3s from your computer on the big speakers and so that you could play your LP records and SACDs through the rest of the house. This Zone Player would not have its loudspeaker outlets connected to anything. You would have another Zone Player in your master bedroom closet, driving two sets of speakers in parallel. The first set of speakers would be conventionally wired to the Zone Player. The second pair of speakers would be in the ceiling of the master bathroom, connected by wires that terminate in a wall-mounted jack inside the closet. You would have a third Zone Player in your home office, next to your computer, because although the Sonos Desktop software runs on a Windows machine or Macintosh, the computer itself won't play what the Zone Players are playing. You might have a fourth Zone player in your kitchen.

I set up a system as described in the previous paragraph in approximately 15 minutes, including informing the Sonos software of the location of my music library, which it indexed in a background process.

Its basic capabilities put the Sonos system far ahead of the alternatives in terms of compatibility with legacy stereos and TVs but the details make the system even more impressive.

Network Connectivity. Sonos wants at least one of the Zone Players plugged into a hard-wired Internet connection. Unlike almost any other product on the market, Sonos refrains from hogging the "drop". The back of the Zone Player sports four RJ45 jacks. If you previously had a computer plugged into a network drop, simply run a cable from any of the Zone Player's four ports to the wall and connect the computer to one of the remaining three ports on the Zone Player. A single Zone Player will find other Zone Players on the wired network and also any that are within range of its 802.11n Mbit wireless network transceiver. The Zone Players cooperatively set up an encrypted wireless network that requires no configuration by the consumer and is independent of any wireless network that might have been set up in the same apartment for laptop computers. The encryption ensures that your tech-savvy neighbors can't sniff packets and figure out that, while you've been crusading against rap music at PTA meetings, at home you enjoy Ice Cube's Death Certificate. An unadvertised features of the Sonos system is that it forwards packets it sees on the wired network. Suppose that, for example, you have a McMansion, where a single WiFi base station won't cover the whole house. If you have six or eight Sonos boxes they establish a mesh network where wireless packets need never travel more through one or two walls. You can then plug a laptop or desktop computer into the back of a functioning wirelessly connected Sonos box and it will provide connectivity for the computer.

Legacy Sources. The Sonos's analog line input digitizes signals from a legacy stereo or television at the standard Compact Disk sampling rate of 44.1Khz, 16 bits per sample. If you are only going to play one of these sources at a time in the house, go to "File -> Preferences -> Advanced -> Line-in Encoding Uncompressed" in the Sonos Desktop Controller software to make sure that you don't have compression enabled. The line output level is a bit lower than standard audio components so crank up the volume on any Sonos box that is feeding a legacy stereo.

Party Mode. For those of us who don't have $2-3 million to spare for a single-family home and are forced to live in cramped squalid condo apartments, Sonos offers "party mode" in which changing the source or the song for one Zone Player changes it for all. If you are sensible enough to live in a part of the country where you can afford a house large enough to support different music in different rooms, the Sonos will let you play 32 different streams in 32 different zones. You can switch between "party mode" and ad hoc linking of zones either from the Sonos Desktop Controller on a PC or from the Sonos remote control.

Remote Control. Sonos used to make a wonderful hand-sized remote control unit that talks to whichever Zone Player is closest. Here's what I wrote about it:

The controller shows you album cover art, if available, what track is playing, and what track is next. Volume control gets dedicated up, down, and mute keys on the left. The controller has a wheel-style control like an iPod plus a huge display with soft keys. The rechargeable remote control has a motion sensor and wakes up if you pick it up, or if you touch any key. Sonos makes a charging cradle that you can mount on a wall and the remote is splash-resistant if you want to change tracks while sitting in the bathtub.
This was a perfect device. They don't make it anymore. Instead you install a free app on your Android or iOS device. Unfortunately, the typical Android or iOS device has 100 other apps installed and it takes a while to boot up the Sonos app. The touch screen of a phone or tablet is not as simple to operate as the volume control button was on the Sonos controller. Waking up a conventional phone or tablet and navigating to the Sonos app is simply too much work and takes too long for the desired operation of changing volume. Perhaps with Android it will be possible for someone to reprogram the software so that the device always wakes up in "Sonos control" mode and additional steps are required to get to any other app.

Subscription Music. Sonos works nicely with all of the subscription music services, such as Rhapsody, Pandora, Spotify, MOG, etc.

Music Purchased Online. The iPod/iTunes world opened up in 2009 and Sonos can play newly purchased DRM-free iTunes tracks. If you got suckered into buying DRM-crippled tracks, the only way to play them on a Sonos is to strip out the DRM with the free JHymn program. Note that using this program in the United States, even to play music that you paid Apple for, may be a criminal act in violation of Bill Clinton's Digital Millennium Copyright Act (DMCA; 1998). The Zone Players can deal with files in any of the popular formats, e.g., MP3, WMA, AAC, and WAV, so barring a DRM issue you should be able to play any music obtained from any source.

Boxes with built-in speakers. Sonos makes a $300 very compact system that includes speakers. It sounds surprisingly good. They also make a $400 moderately compact system that includes 5 speakers and somehow doesn't sound as great as it should. I would recommend the $300 Sonos box for a bathroom and to stick with conventional Sonos AMP players and bookshelf or in-wall speakers for other rooms. Sonos makes a $700 subwoofer that I have not tried, but it looks like a pretty good design.

All is not perfect with the Sonos system. The line input introduces about a 100 millisecond delay. If you hook up one Zone Player to your legacy stereo, for example, and play an LP record or SACD that is then broadcast to other zones, the music will come out of the speakers on those other zones just a little bit later than it came out of the main stereo speakers. This is very evident with percussion. If your legacy source is a preamp or receiver with a tape monitor loop, the solution is to connect the Zone Player via the tape monitor loop. When you want to play a legacy source throughout the house, set the legacy stereo on "monitor" so that you are actually playing from the analog line output of the Zone Player. Now everything is in sync but you've compromised the sound quality of the legacy stereo to some extent. Whereas before you had your $1,000 phono cartridge and $5,000 turntable feeding your $5,000 preamp or your high bitrate Super Audio CD, now everything must go through the Zone Player's CD-quality analog-digital and digital-analog converters.

Additional criticisms of the Sonos system:

Where to buy? amazon.com

Cisco

Here's what I wrote back in 2009:
At the January 2009 Consumer Electronics Show, with great fanfare, Cisco introduced a whole-house music system that is ... almost identical to the Sonos circa 2005. You can see an example at amazon.com. Cisco had four years to study the Sonos product and its acceptance in the marketplace. Cisco has billions of dollars in capital. How did those advantages translate into a better product for the consumer? Cisco has a touch-screen LCD on the front of each of its boxes, whereas the Sonos has only volume controls and mute. Cisco makes an all-in-one box that incorporates a pair of speakers. It is a good product, but so similar to the Sonos that one wonders if it isn't using the same software under license.
What about today? How well did the world's biggest networking company fare in competition with the puny Sonos? Cisco discontinued this product line, leaving consumers with expensive orphan devices.

Which Bookshelf Speakers?

With the Sonos AMP boxes, you are free to use virtually any conventional loudspeaker. The smallest and least expensive B&W speakers are usually about $500 per pair and sound great (e.g., the B&W 686). A less expensive option that has won a lot of comparison tests is the Audioengine P4 (passive version of a very popular powered speaker). I have the Audioengine P4 and a NuForce Dia DAC/Amplifier driven by my desktop PC's optical digital output. The combination sounds great (the speakers are on little angled stands from Audioengine so that the tweeters point directly at the ears of a person sitting at the computer).

Which In-Wall Speakers?

Choose in-wall speakers carefully. They are going to become part of your house and it will be expensive to change them. Most "architectural" speakers are low quality and designed for quiet background music (www.smarthome.com will sell you some), but monoprice.com (see below) is a much better value. The next step up are speakers that cost $100-200 and have the usual mid-fi faults of bumped-up mid-bass and cheap tweeters. Niles Audio is probably the best vendor because they've been around forever. The audiophile's choices start at $300-500 per pair and it is best to deal with a well-established company so that if you need a replacement part in 5 or 10 years you can find it.

Traditionally in-wall speakers are rectangular and in-ceiling speakers are circular. Functionally they are very similar, but most listeners find it more natural to face a pair of speakers and therefore in-wall speakers are preferred except for surround or background music.

For a small to mid-sized room, any of the B&W in-wall speakers will provide excellent sound quality starting at about $500 per pair. B&W's larger and more expensive speakers will deliver more bass response. If your goal is to drive these with a Sonos amplifier, it works fine to hook two pairs up in parallel. I recommend the 14-gauge in-wall speaker from monoprice.com, which also sells two-speaker wall plates with 5-way binding posts. Get all of the hardware and any electrician can easily put the speakers in and run the wires back to the wall plates (don't forget to put the wall plates near a power outlet so that you can plug in the Sonos!).

In November 2012, I had South Shore Audio Video (Boston area) install a 7-room system based on Sonos and speakers from Monoprice. The wiring (14-gauge) and wall plates were also from Monoprice. I tried the following speakers:

The Sonos 55-watt amplifiers had no difficulty driving two pairs of these speakers (in parallel) to moderate listening levels in my relatively small rooms. Unlike standard competitive products, very few of the Monoprice speakers offer tweeters that can be aimed, which means the high frequencies will be faint unless the speakers happen to be positionable so that the tweeters are pointed at the typical listening position. Bumping up the bass electronically with Sonos equalization yields only a small improvement in the richness of the sound. The conclusions on Monoprice speakers so far seem to be (1) that they are most suitable for use with a subwoofer (i.e., an actual woofer!), (2) that they sound about as good as other cheap speakers but are potentially even cheaper.

It costs about $200 per room in labor to have speakers cut in by professionals and the wires run back to a wall jack. The South Shore crew did a great job in my place, which is challenging due to the 120-year-old lath and plaster walls. Kirk, the owner, personally showed up both at the start and end of the job to make sure that everything was working properly.

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Text and pictures copyright 2005-2012 Philip Greenspun
philg@mit.edu