MP3 Convergence on a Dime

Use your old hardware to set up a shared MP3 audio system

Moore's Law—which states that each new-generation computer chip contains twice as much capacity as its predecessor—combined with effective marketing and ever-better computer games, has pushed the PC hardware envelope, leaving many of us with old yet still capable systems. Even though high-speed video and graphics requirements have rendered much of our hardware obsolete, we have a unique oppor-tunity to recycle legacy hardware in home theater or stereo setups. Convergence defines the merging of computers with more traditional electronics to provide improved features and functionality.

The benefits of using a standard computer for your home MP3 system really shine when you consider all the terrific software available. Dozens of MP3 players, beat-mixers, faders, remote-control packages, DJ effects packages, and other fun products can enhance your MP3 player beyond the capability of simply playing a song list.

Using a mix of old, inexpensive equipment and new cutting-edge components, you can build a high-fidelity MP3-player system that's accessible throughout your home. In addition, you can set up a centralized server to share MP3 files with both a locally connected home stereo system and other computers in the home. Creating audio CDs from your MP3 system so that you can play MP3 music on the road or on other conventional stereo systems is a simple process. However, before you start spending time and money in support of the MP3 format, you need to understand and buy into the technology.

What's MP3?

MP3 is the Moving Pictures Experts Group (MPEG) Layer 3 audio standard for coding audio information in a compressed digital format. Because no single company owns this standard, MP3 has widened the playing field for software-based encoders and players. CD audio also adheres to a standard format—called Compact Disc-Digital Audio (CD-DA—aka Red Book)—which Sony and Philips introduced. Both CD-DA and MP3 are digital formats, but MP3 provides 12 times as much digital compression and audio-storage capacity as CD-DA. MP3 is roughly equivalent to fitting 14 hours of music on a 74-minute CD. When you encode music in the MP3 format, you can select the sampling rate. The sampling rate is the time interval between samples, or subsequent reads, of the music by the encoder. A higher sampling rate (i.e., a shorter interval between samples) yields a better-sounding reproduction, but the encoded file will necessarily be much larger. A typical sampling rate of 128Kb/sec results in approximately 1MB/min of recorded music. Lowering the sampling rate sacrifices quality for quantity.

MP3's compression algorithm reproduces the original sound with minimal degradation. You'll probably be able to distinguish CD sound from MP3 sound if you perform a back-to-back test on a high-quality stereo system. However, for the average listener, distinguishing between formats—particularly with a rock, rap, or pop recording—is difficult, especially when you're listening to a low-fidelity stereo system. MP3 is ideally suited to being stored and played on your stereo system because of its combined high fidelity and compression ratio. Other formats, such as Windows Media Player (WMP) and Liquid Audio, offer such advanced features as digital rights management and better compression than MP3; however, MP3 is more popular and has already begun to infiltrate traditional electronics (e.g., your car's CD player). The MP3 format is a good choice if you want to transport your music between different systems.

Why Not a Dedicated Player?

As recently as last year, MP3 was relegated to PC decoders. During the past 6 months, mainstream companies have started pumping out MP3 players in every shape and size, and personal MP3 players are becoming extremely popular. A few vendors are offering players for the automobile—either with built-in storage or the capability to read MP3 files off a CD-R disc created on a home computer. Bose recently introduced the Wave/PC, a device resembling a tricked-out clock radio that connects to your computer with a 15-foot cable and lets you assign MP3 playlists to station presets. Although the Wave/PC is expensive (i.e., about $450), its development is a big step forward in MP3 adoption.

Typical stereo components (e.g., audio/video—AV—receivers, CD players, cassette tape decks, turntables) have specific functions. Today, you can also purchase dedicated MP3 components for your stereo system, but the price is relatively high—starting at about $500. (To put that cost in perspective, consider that you can buy a good-quality AV receiver—the heart of a stereo system—for the same price.) These dedicated MP3 devices play only MP3 files. Because a dedicated MP3 player is designed to be part of a stereo system, it will physically match your other stereo components and won't suffer from the grounding problems or fan noise that might plague a computer-based MP3 player. However, a dedicated MP3 player limits you to a specific software and feature set and limits your ability to freely upgrade rapidly evolving software. Building your own MP3 player isn't as convenient as buying a dedicated component, but it's less expensive and permits complete customization.

Start with What You've Got

Even if you have only one PC, you can take advantage of some of this article's tips. However, because the hardware and cost requirements are relatively low, consider picking up a dedicated PC. (For the base system that I discuss below, I paid less than $100 at an auction.) Using a dedicated system is convenient—you can listen to songs through your home stereo system and avoid broadcasting your AOL connection's "You've Got Mail" message to your neighbors!

In "How to Set Up an MP3 System" (available online at http://www.connectedhomemag.com, InstantDoc ID 22445) I build a system that is more than capable as a dedicated MP3 player. The OS's GUI, the music-playing software (commonly called the Jukebox program), and other add-on software increase the system's functionality and consume most of the processing power. If you trim back functionality, you could use a less-powerful system.

One of the rewarding and challenging aspects of this project is getting newer software to run efficiently on vintage hardware. For example, the predecessor to the base system I describe in "How to Set Up an MP3 System" consisted of a 50MHz laptop with 8MB of RAM that ran Linux. Older laptops are great because they're smaller and quieter than their desktop siblings. You can build a functioning MP3 system with a base system such as the one that Table 1, page 27, describes.

Set Up the Base System

The selection and architecture of your base system might affect the deployment of your dedicated MP3 player. Spare parts' compatibility with newer components can limit the expansion of an MP3 system into your stereo or home theater system. You need to review your components and decide whether your base system is suitable. If your system doesn't support a particular function or format, think creatively. Likely, a cheap workaround exists. For example, if your PC doesn't have the RAM or the processor to support a full-GUI Windows MP3 player, consider a command line­driven MP3 player or try a less resource-hungry OS, such as Linux.

Unless you have a specific task or application that drives your platform choice, you should select the platform with which you're most familiar or can best support. Both Windows and Linux offer many tools for managing and playing your music. In "How to Set Up an MP3 System," I'll walk through different approaches to setting up a dedicated system that lets you affordably extend your home stereo system into an MP3-playing jukebox. Join me online to discuss system requirements, audio-hardware component reviews, and jukebox software information. I'll also describe general ideas for managing your music from a central location while making it available to all the other computers in your home.