The idea to build my own home theater box came to me one day as I hooked my new DLP HDTV up to the huge stack of components piled next to it. My stack had an audio amplifier, an aging Series 1 TiVo, an HD cable box, a DVD player, another DVD player with upsampling, an X-box, and a radio tuner. If you’ve ever hooked up a set of components like this, you know there are literally dozens of ways to wire it up and make it work halfway coherently with a multi-function remote.

I should know: I’ve been hooking up, configuring, and re-reconfiguring these components for more than a decade, through several eras of technology. That there isn’t one of the original components in the stack is irrelevant, though, because I still consider it the same stack.

The entire collection was obsolete. Modern sound cards and computers have more than enough compute power to do virtually unlimited signal processing on an audio signal without a dedicated digital signal processor (DSP). I needed only one type of video going into the TV; all the old analog stuff could be intercepted and turned into nice, civilized digital signals before it ever got there. One media center PC could do the entire job.

The Requirements List

Having decided to embark on my quest to build the ultimate media box for my home theater room, I decided to do this project the right way and choose my parts first. Normally, I have two methods of doing these kind of projects: the professional way that I do it at work, and the DIY way of buying a bunch of random stuff that’s on sale and forcing it to work together with hammers, screws, and software patches. This way I figured I wouldn’t be building another Frankenstein computer, adding to the boxes of expensive obsolete components that I have under my bench in the garage.

Ignoring the evidence that I live in a house full of kids who like to touch my stuff, I managed to get into the professional mode. This clears the mind of useless clutter like, “why is there another picture drawn on the back of the front door with a Sharpie?” The clutter faded like white noise, leaving me with crystal clear mental pathways to building the new box.

While working a professional project, I start with requirements. This sounds dry and boring, but what it really expresses is an engineer’s desire to 1) not to reinvent the circuit board, and 2) not to waste time doing unnecessary work that keeps me away from the really expensive toys in the lab. So I took a few seconds to develop my requirements:

1. The Home Theater Control Center shall do everything.

You really have to admire the simple elegance of my list. It’s tight and internally consistent – a welcome change from most customer requirements.

That out of the way, I got down to the business of building stuff! Or at least thinking about building stuff, which is almost as fun. Ignoring for the moment that the definition of “everything” needed to be narrowed down a bit, I started to list the GZINs[1] and GZOUTs[1].

Ideally, you’d be able to buy a Deluxe Super Whiz-bang Home Theater Card with all the features you need and a couple dozen connectors. A quick ‘tubes google taught me that there isn’t any such thing. It also taught me that there are major issues around the use of DVI and HD format disk players. But more about that later. In any case, the GZINs above only really tell you what kind of input you have available, which isn’t necessarily the same thing as a list of the functions inside the box.

So I made another list:

It looks sort of like the same list, but it isn’t. The first list is interface types; the second list is function types, with various crossovers. Breakdown by function is useful in choosing hardware with as little overlap as possible and covers all the required functions.