Expert Viewpoint: Powering the Home Theater
Sep 1, 2008 12:00 PM, By Marshall Currier
Power management helps meet expectations for high-end home theaters in luxury condos.
Factories and other older buildings that have been converted into luxury condos come with a high price tag and thus attract high-end clientele. For such a unique, distinguished home, the inclusion of a home-theater system is understandable — and discerning clients will expect nothing but the very best audio and video quality, as well as maintenance-free performance.
For the AV professional, installing home theaters in old buildings and meeting user expectations raises a number of architectural and power-based issues. Renovation of an old building in general tends to involve a full restoration of the electrical system, because old buildings will often provide no ground wire and will have aluminum instead of copper wiring. That being said, installers must be concerned with protecting the performance of the system, shielding components from the power fluctuations that plague older buildings, and working around architectural challenges to install remotely located components in an aesthetically pleasing manner — all while avoiding inconveniencing the homeowner with regular service calls.
All of these issues can be addressed by using proper power-management solutions.
For AV professionals, optimizing the performance of home-theater components in any residential installation is a primary concern; component longevity is often the defining issue for the user. The goal for the installer is to meet both objectives: providing the best sound and video quality, while protecting equipment from power anomalies that can damage or even destroy electronic equipment.
The challenge in achieving this goal lies in the fact that the power coming out of electrical outlets is not 100-percent clean and stable, especially with older buildings being even more susceptible to power fluctuations than newer structures. And while the ultra-sensitive circuits in today's professional AV equipment are technologically superb, they are also very fragile.
Therefore, when installing a home-theater system into an old structure, it is imperative to employ an advanced power-management system. A comprehensive power-management system will filter out the AC noise present on the line for improved component performance, while at the same time protecting connected equipment from spikes and transients that are all too prevalent in today's utility systems.
AUDIO AND VIDEO QUALITY
Power is contaminated with noise from a variety of sources, one of which is the proliferation of noise that is produced by computers and microprocessors that receive power from a switched-mode power supply (SMPS). The list of sources in the household containing these small devices is endless. This noise severely impacts AV performance by masking much of the detail needed for the best possible sound staging and video image resolution, and it can affect the reliable operation and longevity of today's sensitive equipment.
To significantly improve video and sound quality, a power-management system acts as a filter, reducing much of the undesirable noise on the AC line and thereby preventing it from interfering with AV signals. There are two fundamental types of noise: differential mode (asymmetrical noise from appliances) and common mode (symmetrical noise such as 60-cycle hum from ground loops and RF noise). When filtering AC power, it is important to reduce the level of noise linearly (evenly) — which eliminates common symptoms of AC line noise, allowing equipment to perform at full capacity for an optimal home-theater experience. If an AC filter is not designed for audio and video components or linear in its filtration type, resonant peaking can potentially add additional noise to the AC line, as if no AC filtration were present in the first place. Isolated outlet banks on a power-management system prevent any noise generated by a component within the system from contaminating or back-feeding noise to other equipment plugged into an adjacent outlet bank.
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