Our aim in developing the original (passive) LCi Series of loudspeakers was to create flush mount speakers for serious listeners " people who are passionate about music and audio who prefer to have the cosmetics and space saving benefits of in-wall and in-ceiling speakers.
The IP versions discussed here are the world's first truly high performance self-powered Internet Protocol-enabled loudspeakers. They were designed to be used within TCP/IP based multi-room digital audio distribution systems such as NetStreams DigiLinx to provide a wealth of performance and convenience benefits. When used in analog systems the built-in power amplifiers and Digital Signal Processing continue to provide sound quality that is unequaled by any other built-in speaker system regardless of price. In fact the LC265i-IP may be the only built-in speaker capable of exceeding the performance of high end free-standing speakers.
Our focus will be on the rectangular in-wall LC265i-IP. Most of the design features and technologies discussed also apply to the round in-ceiling LC80i-IP.
The conventional way of distributing audio signals throughout a house is to have a centralized rack of high powered amplifiers connected to speakers in various rooms via hundreds of feet of (usually low quality) speaker cable. As a result signal fidelity is degraded over the long runs of speaker wire Control of such conventional analog systems usually involves customized programming of keypads and other control devices—an expensive and time consuming process that does not allow for easy scaling of the system. The post-installation addition of even a single new source component can cost the homeowner thousands of dollars in programming changes. Additionally these systems are often difficult and non-intuitive to operate.
In contrast, a system using the Internet Protocol standard distributes uncompressed digital audio (up to 24-bit/96kHz) throughout the house via CAT5e cable to amplifiers located nearby or (in the case of Polk's IP speakers) inside the speakers. The signal is converted to analog only at the amplifiers' outputs, thereby maintaining perfect, lossless fidelity throughout the house. As the signal remains in the digital domain into the Digital Electronics Module on the back of the Polk IP speaker, bi or tri-amplification and digital signal processing is far easier to accomplish.
In an IP based system, all source and amplifier/speaker components self-announce themselves to the rest of the system, vastly reducing the amount of programming and installer involvement required to install or add to the system. The NetStreams DigiLinx system is scalable and supports an unlimited number of sources and rooms. IP based systems can be controlled by any Internet enabled device such as PCs, wireless web tablets, PDAs or purpose-designed wall keypads.
To quote from NetStreams; website:
"NetStreams' DigiLinX IP-Based Multi-Room Audio distribution offers super high quality multi-room audio and control. The DigiLinX system distributes audio over CAT5e using TCP/IP on a segmented section of an Ethernet network " the Home Entertainment Network, with no additional networking equipment requirements. DigiLinX converts audio from a legacy source, in real-time, into uncompressed audio streams (.WAV), allowing up to 24-bit/96kHz, studio quality audio to be distributed throughout a home or commercial facility. The level of audio performance is limited only by the quality of the source material.
DigiLinX's scalability and expandability is unmatched in the industry, with the system supporting virtually unlimited sources and rooms. By eliminating the quality and quantity limitations of traditional matrix switchers, NetStreams has obliterated the traditional source and room limitations of current systems.
Each DigiLinX component contains its own IP address and web server that can serve-up rich control pages to third-party products such Web Tablets, Pocket PCs, Web TVs, or computers, for a new experience in music management."
The Polk Digital Electronics Module
On the back of the LC265i-IP speakers is a small aluminum enclosure that houses the amplifiers, provision for the addition of an IP interface card and the Digital Signal Processing (DSP) Engine. The module has Ethernet ports for connection to digital systems, dual RCA jacks (for use in analog audio systems), power connectors for the 48V DC supply and a mini-USB jack on the front baffle of the speaker. Wiring an IP audio system is accomplished via "Siamese" cable of CAT5e (or CAT6) Ethernet cable wedded to speaker wire. The Ethernet cable carries audio and control digital data while the speaker wire carries the 48V DC current from a remote power supply. When wireless networks become robust enough to handle uncompressed digital audio signals without dropouts or latency, the Ethernet wire can be eliminated. Unless someone invents a high voltage, high current battery that can last for a year without a charge, or a palm-of-hand-sized nuclear home reactor/generator there will never be a truly wireless speaker. In the meantime many new homes are being pre-wired with Ethernet cable for a variety of data and home automation functions and an IP audio system can work on the same backbone.