The most common and least expensive way to route music from your computer to your stereo system is to run an RCA audio cable from the sound card on the computer to the stereo receiver. All sound cards are made with at least one Line Out jack, used to power computer speakers. The jack is normally a 3.5mm mini phone plug. An inexpensive adapter that features a 3.5mm stereo jack at one end, and two female RCA jacks at the other will work well here. This will connect to a standard RCA stereo cable. The opposite end of the cable will plug into the stereo or surround sound receiver. Here you’ll need an available Audio Line In RCA port, which may be marked Aux for auxiliary.
After the connection is made, set the volume down before powering up the receiver. Change the receiver mode to auxiliary (rather than tuner, CD, DVD, TV, etc.), and slowly turn the volume up. You may need to boost the volume control of soft MP3 player as well.
Advanced sound cards might also have other Line Out options, such as Digital Out. The instructions are the same, substituting a digital cable for the RCA cable. The receiver will also need a Digital Audio-In port.
Though wired methods are inexpensive, they have the disadvantage of requiring a physical cable to run from the computer to the stereo system. If the computer is a desktop located in a different room from the stereo or entertainment center, this can be impractical. A laptop provides a good mobile medium for music libraries, as it can be set rather close to the stereo system to simplify things and keep wires out of walkways.
When hard wiring your music connection isn’t practical, another method is to go wireless. In this case a small transmitter is connected to the Line Out port of the sound card, and a matching receiver is connected to the Audio Line In port of the receiver. Music from the computer is silently broadcast via radio waves from the transmitter to the receiver. The receiver interprets the radio signals and translates them back into an audible signal to play through the speakers of the entertainment center.
Wireless stereo transmitters vary in design and pricing and a few models are expressly designed for iTunes music. Others include composite video ports to send not just audio, but video signals between the computer and entertainment center. Cables might be included or sold separately. For more information check your local electronics stores or your favorite online retailers.
