June 2003
If these walls could speak…
Wouldn’t you like to play music throughout your house, including the back porch, the upstairs bedrooms and the kitchen? What if you could customize the music to the different tastes of family members, playing jazz in one room, classical music in another and rock ’n’ roll in another, all through the same entertainment center?
Since the invention of recorded music, homeowners have searched for new ways to fill their homes with the sound of music. Now with affordable computers, home networking, speakers and audio equipment, the grandest imaginings of whole house audio are within everyone’s reach.
Good, Better, Best
Many options exist for whole house audio. The simplest way would be to direct the same signal at the same volume throughout the house. A better system would allow for volume control in various rooms or areas of the house. The best system would allow different audio signals or channels to be sent to different zones throughout the house.
Category 5e (or Cat 5e) structured wiring is the new standard for high bandwidth communications wiring within homes. Cat 5e wires are inexpensive, high performance twisted-pair wires. Many homeowners are now rewiring with Cat 5e for home networking, and when this is done it is just as easy to include whole house audio, too.
Regardless of how modest or ambitious your whole house audio plans, it makes sense to install Cat 5e wiring and speaker wires at the same time. Once the wires are in place, speakers and amplifiers can be distributed throughout the house according to the needs and budget of the homeowner. And Cat 5e structured wiring opens the door to other possibilities, such as whole-house security systems and even home video-camera networks.
From an electronics point of view, the most important thing to know about audio is that there are two types of audio signals: speaker-level signals, which are power amplified; and line-level signals, which are not power amplified.
Audio Wires, Big and Small
Line-level audio comes from the output of devices such as CD players, DVD players and other non-amplified sources. These low-power signals must be connected to an amplifier in order to operate a typical home speaker. And these low level signals can be transmitted over Cat 5e cables no different from those used to network the home computers.
Amplified signals are high-power signals that originate at the speaker outputs of power amplifiers, or from amplified volume controls. These speaker-level signals are typically carried on 16 AWG or 14 AWG speaker wire. In sophisticated, high-end systems, the wire size may range up to 8 AWG (lower AWG numbers indicate thicker wires and less electrical resistance). For convenience, amplified signals may be attenuated (or reduced) by speaker-level volume controls in the room where the speakers are located.
Putting It All Together
An optimum setup is to send non-amplified audio signals to an amplifier that serves the particular speakers in one area or room in the home. Speaker wires can be run through the walls from the amplifier location to individual speakers, which in some cases can be built into the walls or ceilings.
The key to whole house audio is the in-wall wiring. Other quality components, such as speakers, amplifiers and audio sources are indispensable; but the wiring is the defining difference between whole house audio and single room sound systems.
For additional information about residential communications over copper wires, visit our Telecommunications section.