Tuesday, August 9, 2011

The $100 Home Theatre

Let me start by warning that although this post is about a successful project, it begins with a eulogy for a much-cooler project that met an untimely end.


For a long time I've wanted a home theatre -- but I've always been afraid of the beer-bellied middle-class suburbanite status that having one would give me. So I thought I'd make my own, DIY-style, and avoid having Future Shop rifle through my wallet for carrion. This quest started a few years ago when I heard that you could make a cheap home theatre out of an old LCD screen and a transparency projector.

An LCD screen works like this: at the back of the unit is a big, rectangular backlight, basically a fluorescent tube, that generates a white light. Sitting between that and the viewer is the LCD screen itself, which is a grid with hundreds of thousands of squares (pixels). Each of these pixels is further divided into three squares for each of the primary colours -- red, green, and blue. Each trio can selectively block the light from the backlight to mix colours, or block the light entirely to make a black spot. Thus pictures are formed.

Often the backlight or its power circuitry will burn out, leaving the display unusable. You can get these for almost nothing. A long time ago, someone had the idea of removing the defunct backlight and placing the rest of the display on an overhead transparency projector, making a cheap movie projector. (In fact, I remember finding a similar commercially available product in junior high.)

Here's what one of these looks like -- made by someone else.



It sounds like a jet engine and the picture quality isn't great, but you have to admit that makes an impression.

The Caprice

I'm also a sucker for antique stereo equipment, and by antique, I really mean antique -- not the usual 5-years-or-older kind of antique that plays with computer equipment. I came across an RCA Victor record player from the '40s or '50s and decided to build the projector into it.


And here's a close-up of that spectacular logo on the front:


I'll be damned if I know what "Orthophonic High Fidelity" means -- there's some history here -- but under the hood was a pretty conventional tube amplifier and electric phonograph. All dead as a doornail except for the exciting shock I got from the cartridge wires when I plugged it in.

I gutted the chassis and adapted it roughly for its new task. It was going to contain the high-power light and lens from the overhead projector, the LCD panel, and underneath it all, a small all-in-one motherboard from an Asus Pundit.

Here's the gutted chassis adapted for the new hardware:

Believe it or not, this actually worked despite the rough craftsmanship (which was covered by the bezel of the LCD panel). The slot cut out of the right-hand side was for the spare-bulb lever from the overhead projector -- if the bulb burnt out you could slide the lever up to change in a spare.

On the back I but out space for the cooling fan and installed a grille.


(Note the model name for this record player: The Caprice.)

I had it successfully rigged up with some duct tape and old books in place of better structural engineering -- and successfully played one of my favourite movies on it.

Unfortunately there the success story ends. This all happened in 2005 or 2006; I spent a few months overseas, and a friend of mine shattered my cinephile dreams by gently resting a couch on top of the LCD display in my storage locker. The whole project was built around this quirky display and I couldn't face the prospect of scavenging the rest and trying again.

I still have the record player chassis and await anther interesting project for it. The Fresnel lens from the projector hung around on my windowsill until sometime last year when I discovered that it was trying to kill me -- it focused the summer sun on my bedroom curtains and probably came very close to burning the whole building down.



Take Two

Jump forward about 5 years. Enter Free Geek Vancouver; LCD displays are no longer rare and exciting, and now come in as donations. It's no longer necessary to sniff around Craigslist for broken ones. But better still: we've actually started to receive donations of working LCD projectors. I've dusted myself off from the earlier tragedy and am ready to give it a second try.

Using an LCD projector instead of making my own changes the nature of this project. The inspiration behind the first one was to see whether I had the technical skill to build it. For the second one, I found myself staring at all the pieces -- expensive, high-quality pieces -- at the receiving desk at Free Geek Vancouver.

The trickiest piece of this to come by is the projector. We've probably sold fewer than 10 of these since the place opened; they don't come in very often. But sometimes a school will get rid of its oldest equipment:

This is a Sony VPL-S900, a tank of a unit from the end of the last millenium. It runs at 800x600 resolution, which is lower than new projectors, but still higher than the resolution of a conventional DVD.

I also pulled a decent home theatre amplifier out of the recycling bin at Free Geek -- I do this periodically with staff permission if I see something interesting getting chucked and can usually take a toy home for a few dollars.


This unit is over a decade old, but it was a great unit then with a lot of modern features like optical inputs. It already had its power cord amputated, but I soldered another in without too much difficulty.

All that's left to add is a screen -- I got some blackout fabric from Dressew and a brass grommet kit from Magnet Home Hardware. A little of this:


...and I have a pretty fair screen that I can bungee-cord to the wall.

Forgive the mess; that's another project sitting on the floor.

That's over 100" diagonal, with a wide-screen aspect ratio. The bungee cords tension the screen evenly to keep it fairly flat.

To feed it, I finally ended up taking my adoption box home. It's a very normal adoption box; the only thing I added was an audio card with an optical audio out.
(I didn't want to run analog audio all the way across the room from the computer to the amplifier, as there's the potential for noise.)

I've got four speakers -- in front, two big Magnasonics (that's right, neither Panasonic nor Magnavox) that I got from a garage sale when I was in my teens. They don't sound half as bad as that suggests. At the back of the room, I have two little Sony satellite speakers -- another $5 or so at Free Geek.

The only thing I got new was a 40-foot fiber optic cable, $6.80 + shipping at Monoprice. Every single piece aside from that was purchased used.

Here we go!



The quality is much, much better than it appears in this video, but you'll have to trust me on that unless I invite you over to watch something.

OK, so what's the big deal, Alec? You got a bunch of stuff at Free Geek and you're too busy bragging about it to watch movies.

The point I'm trying to make is amply illustrated by this graph, stolen from retrevo.com's review of the AVR-500:
This graphic appears alongside the overwhelmingly positive reviews of the amplifier. What does it say? It's old, you should replace it. Not because it's broken, not because it sounds bad, but simply because it's old.

This makes me angry. Why? Try the math:

LCD Projector. Year: 1999. Retail price: >$6000 CAD.
Amplifier. Year: 2000. Retail price: >$4000 CAD.
Computer. Year: ~2008. Retail price: >$1000 CAD.

There you have it: an $11,000 home theatre setup, without even counting the speakers. Total cost to me is less than $100. Is it lower quality than a brand-new setup? In some ways, yes -- I won't get the full quality of an HD DVD projector. But these are not just entry-level components; they are among the highest-quality of their day. And I'm not alone in thinking that the quality of consumer electronics might be decreasing, not increasing.

These are all pieces that were donated to Free Geek because they were judged to be beyond their working life. While I'm grateful that people are donating the equipment rather than throwing it away, I have to wonder why they're replacing it.

Look: the audiophile world is trying to rip you off. Amazon is trying to sell you gold-plated fiber-optic cables -- when gold plating is totally irrelevant to the quality of the cable. Denon famously sold a $500 cable that is totally indistinguishable from a $5 network cable.

I've heard lots of arguments about manufactured obsolescence -- the idea that equipment is made to fail so that it will be replaced sooner. And I agree -- with things like printers being among the worst offenders. But when the gear being replaced is perfectly good, it's a social issue, not a technological one...

Postscript: The $10 Home Theatre

So I was feeling pretty good about all of this when I went to volunteer at Free Geek last Thursday. I was not expecting to discover the key ingredient for an even cheaper home theatre. But here it is:


This is the oldest LCD projector I've ever seen. It's a General Electric and according to the Internet it barely exists. I'd guess it's from sometime in the '90s.



It takes an NTSC input (i.e. it would plug happily into a VCR or a DVD player) and it works. It'll need a new bulb soon, and those can be had for around $80.

I put it in the store suggesting that we blow it out for $10 or so to the first curious hobbyist. I hope it makes someone happy.

1 comment:

  1. gorgeous - I just tweeted this. FreeGeek is such a wicked project. keep up the hard work.

    ReplyDelete