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CEDIA EXPO 2000 is being held in Indianapolis, September 6 - 10, Indiana Convention Center. The daily reports will be updated with new content, so check back on each individual day report now and then.
Unlike CES, CEDIA conventions are educational events as well as an industry trade show. CEDIA is the Customer Electronics Design Installation Association, and its members do custom stereo and home theater systems for clients worldwide. Education is offered to members and non-members alike, and it covers technical topics such as home wiring infrastructures as well as custom whole home music and video distribution. Business topics are also covered to help CEDIA members improve the function of their business. Today, I attended the course “Home Networking with IEEE1394 / HAVi”, taught by Bob Perry, a marketing director with Mitsubishi Digital Electronics, America.
What would you say if someone told you “I can get rid of that snake’s nest of wires that connects your A/V system”? If your system is as complex as mine, you’d probably take up anyone making that offer immediately.
This course was a glimpse into the future direction of home A/V connectivity using IEEE1394 – more commonly known by the sexier moniker assigned by its inventor, Firewire. The A/V industry has adopted a series of standards that will allow for much easier integration of your home theater components using Firewire. The most basic of these is Audio Video Control. With AVC, basic device functionality can be managed. A more advanced version has been adopted, known as Home Audio Video Interoperability (HAVi).
As our systems become more digitally oriented, duplication of functions will be largely eliminated. Instead, you’ll have one video decoder and one audio decoder. While a single audio decoder (preamp/processor or receiver) is common already, each digital video device still does its own decoding and then passes along the analog signal to the display device. The adoption of IEEE1394 means that the DVD player will no longer require the MPEG 2 decoder. The DVHS recorder also won’t need an MPEG 2 decoder. Instead, these devices will be more of a data recorder and transmitter, with appropriate streams of data passing along the wire towards their intended destinations. In this example, you’d have an MPEG 2 decoder in the display device, namely an HDTV. You’d also have an audio decoder which would playback the audio bitstream in whatever format it’s presented. The net result for consumers is that the cost of components should be reduced, since they will be much simpler devices.
Already on the market, some components are sporting IEEE1394 interfaces for these future home A/V networks. According to the course instructor, by 2002, nearly all A/V gear sold will have Firewire interfaces for integration into the home network. So, when you buy a new piece of gear, all you have to do is plug it into the HAVi network using a single cable, and it will be configured automatically, sort of like we do with USB devices on our computers, i.e., Plug and Play. There is also the capability of integrating non HAVi devices, which will be controlled via IR codes. To help consumers along the path, components that support HAVi will have a HAVi logo, and will be interoperable with other HAVi products. Think of it: ONE WIRE connecting all the components together!
Construction of a HAVi network is similar in many aspects to a home data network today. You’d have a cluster of components connected together in a room, with a single connection out of the room in a “Home Run” to the central HAVi concentrator. With this type of network, any component can communicate with all the other HAVi products. You could have a single CD/DVD changer in the basement of the house feeding the various rooms with DVD sources, while a satellite dish or digital cable signal feeds the live video requirements.
While this type of environment is still a few years away, the framework is being laid now, and if you’re doing a custom home installation there’s one bit of advice I can give you to help prepare for this future: use conduit for any inwall cabling to make putting more cable into the system much easier.
What is Tomlinson Homan up to these days?
When you take a course at CEDIA, it’s exciting to have an industry luminary giving the presentation you’re attending. I walked into the Multi-Channel Digital Audio formats course and had the opportunity to be instructed by Tom(linson) Holman. Tom’s biggest notoriety is from his days with Lucas Films, LTD – where he worked on what became known as the Tomlinson Holman eXperiment, or THX. He started his work in the industry with Advent, working on large screen televisions. Next, he founded APT Holman and made a series of preamplifiers and amplifiers that were highly regarded in their era. He also writes for Sound Professional. His current company, TMH Corporation does consulting projects, including movie studios on sound for their films. Enough hero worship, so what did we learn today? This course was a primer on current digital surround sound formats and an introduction to future surround sound formats for the home.
Our current media is a bit bucket, distributing media as a stream of data (bits). There are three considerations for this media: (1) the size of the data to be stored or distributed; (2) the data rate inbound or outbound; and (3) the requirements for random access, if applicable.
Broadcast media (i.e., HDTV) currently utilizes a bandwidth of approximately 19 Mbps (megabits per second, as opposed to MBps or megabytes per second), and broadcasts must fall within this bandwidth restriction. DVD storage has a lower bandwidth and is limited in storage requirements to the size of the DVD media. That size restriction is approximately 4.5 GB per layer. On current dual sided, dual layer DVDs (such as Terminator 2: The Ultimate Edition), that means each side has two layers. Many people might be aware that some DVD players aren’t handling this kind of disc very well.
There are three current contenders wanting that space on DVD, namely Linear PCM, AC-3 (a.k.a. Dolby Digital or DD), and DTS. The DVD specification is open enough that any or all of these formats can be stored in the audio data portion of the media, and it’s up to the implementer to determine which options will be included. The order of mastering of the DVD determines which menu is the default – so if you aren’t happy with the presented order complain to the studio J.
Mr. Holman presented an excellent primer on the basics of digital audio as well, but I’m not going to delve into them at this time. I will say that his learned opinion is that the current highest resolution formats are overkill for the consumer market, but are required at the recording side to preserve fidelity when the media is processed for delivery to the consumer.
An important lesson learned was recommended speaker placements for proper reproduction of the surround field. In a 5.1 environment, the correct locations should be such that the listening position is at the apex of an equilateral triangle with the front left and right speakers. The center speaker should be slightly recessed from the line of the fronts, so that it is equidistant from the listening position with the mains. Surrounds should be placed behind the listener at an angle of + and - 110 degrees. Per Mr. Holman, dipoles are permissible, which puts me off the hook in my home theater J. In 6.1 surround systems, ideally the center channel should again be slightly offset so that it is the same distance from the listener as the surrounds. This will eliminate time delay errors. If this isn’t possible, be sure to set delays as per your gear’s manual.
There are two current implementations for 7.1 surround (I think we should insist on 7 1/2.1 sound just to slow these guys down in introducing so many new formats). Sony’s theater-based Sony Dynamic Digital Surround utilizes a 5 speaker array across the front of the screen for smooth panning of effects and voices across the front soundstage. Lexicon’s 7.1 surround (Circle Surround) utilizes additional surround speakers, with three fronts, two side effects, and two rear surrounds. The positioning of the front speakers remains the same, with the side surrounds placed at + and - 110 degrees from the listener (as in 5.1), and the rear surrounds at + and - 135 degrees. It’s important to space these speakers equidistant from the listener to prevent surround decorrelation due to the errors in arrival of the sounds from the various speakers.
Tom also described the future 10.2 system which will someday be a standard in the highest-end home theaters. The 10.2 setup utilizes front left, center, and right, elevated front left and right effects, two subwoofers, left and right side surrounds, and three rear surrounds. As before, the front trio remains in the same locations, with the front effects at + and - 45 degrees from the listening position, and elevated in the vertical plane 45 degrees. The side surrounds should be at + and – 110 degrees, and the three left and right rear surrounds should be at + and - 135 degrees. The rear center speaker should be located directly behind the listener, at the same distance as the rear left and right speakers. The subwoofers should be approximately even with the listener at left and right. This is the best compromise for subwoofer locations in the 10.2 environment.
All in all an excellent course with a glimpse into the future of high end home theater environments.
- John Kotches -
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