AV Distribution Via Internet Protocol – The control interfaces for most distributed home AV and lighting systems are now based on IP technology, using PCs, PDAs and other computer devices as controllers. But the content in most cases is still being distributed in analog form via low-level signals to in-room amps, over amplified speaker cable from a centralized system, wirelessly via RF, or some combination of these options. Digital is touted so much that one would think the content is being digitized and streamed over the home Ethernet network, but aside from NetStreams’ system, it is not.
One of the reasons might be the technical challenge of maintaining synchronization. This is not a problem with ordinary Ethernet use of email or streaming information to computers – everyone doesn’t need to receive it at the same instant. However, if one walks from room to room and there is a tenth of a second delay in the sound as you move around, the importance of sync in a home entertainment network becomes apparent. There are a number advantages to sending home entertainment content over an Ethernet network using TCP/IP. Problems of noise and signal loss are solved, no matter what the length of the cable. Signal integrity is maintained perfectly, even for hi-res and hi-def material. Signals can be kept in the digital domain right up until the final loudspeakers. This has been the practice of the higher-end Meridian Audio line for many years now. It eliminates runs of speaker wire which can pick up extraneous signals and suffer from losses of signal. IP-based digital amps located at the speakers keep analog signal paths to a bare minimum. Work is progressing on new IP-based amps which can automatically change crossover frequencies, or EQ based on metadata contained in the IP stream.
There are benefits in installation of distribution systems with IP-based content. Since operation is not dependent on a centralized matrix controller, a failure in one zone can be tolerated without bringing down the entire system. There is also a reduction in labor and materials for installing the cable thruout the home. Industry-standard CAT5 cable is used with modular RJ45 jacks. The wiring reduction saves not only time and effort but reduces later service problems. It is also easy to add any TCP/IP-compliant device to the existing network, without customized programming being required. It is expected that IP-based home distribution systems for both control and content will have a strong future.
