Network Architecture
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The good news is that setting up a computer based audio system has gotten fairly easy; the bad news is that the number of products available and possible network configurations is daunting. We can help you with some basic advice, and provide you with some further resources to explore in developing your own networked audio system.
Storing Your Music
In a simple Desktop Audiophile System the music is stored on the computer hard drive, a player application (i.e. iTunes, Windows Media Player) on the computer “plays” the music, and the music is output digitally to the Desktop Headphone Amp through the computer’s USB interface. There is nothing fundamentally wrong with this basic approach to computer audio and very satisfactory listening can result, but unless this computer will be a dedicated media computer, we highly recommend storing your music on an external hard drive.
The simplest external hard drive connects through USB or Firewire to the computer. This is a very good way to store your music without burning up space on your computer’s hard drive. Drive space is so inexpensive these days that we recommend building a library of uncompressed files for playback at home, and a second library of compressed files for use with your portable media devices.
It’s a little more difficult to set up, but you can also get a “Network-attached Storage” (NAS) hard drive. These drives are not physically attached to one particular computer but are available as a shared hard drive on the network. The advantage of this type of configuration is that multiple computers can easily share a library of music in this drive space. Additionally, NAS drives sometimes contain enough computing power to host a Slimserver or iTunes service. In this case, your computer doesn’t have to be on to play music from the NAS. Simple NAS drives are available under $400; high speed raid arrays can be many thousands of dollars. At some point after a couple of thousand dollars, your best solution may be a full-on media server computer with a fault tolerant raid array of drives.
Network Speed
Wireless local area networks (WLANs) feature different speeds depending on which Wi-Fi standard they support. 802.11b WLANs offer maximum bandwidth of 11 Mbps. 802.11a and 802.11g WLANs offer theoretical bandwidth up to 54 Mbps. Typical wired Ethernet networks achieve 100 Mbps.
The performance of Wi-Fi networks, in practice, never reach their theoretical maximum. 802.11b networks, for example, generally operate no faster than 50% of theoretical peak, or roughly 5.5 Mbps. Likewise, 802.11a and 802.11g networks generally run no faster than about 20 Mbps. Among the factors that contribute to lower than theoretical performance are: protocol overhead, signal interference, and decreasing signal distance with distance.
Full bandwidth audio requires about 2 megabits/sec of network speed for each stream. So, typically 802.11b should run about 2-3 streams of uncompressed audio; 802.11a and g should be able to carry about 8 – 10 full-bandwidth streams; 100 megabit wired Ethernet networks will carry dozens of streams before they begin to bog down.
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