Sunday, November 20, 2011

Theater Connections

It didn't take long after we first opened the theater before one of our children asked if she could connect her game console to it. This was such a great idea that I immediately came up with a plan to make it happen. The cabinets at the front of the theater have three compartments. One is used by the subwoofer and another by the center speaker. That left one position open for a game console, and the obvious choice for adding external connections to the theater.

In order to accommodate a variety of devices, I added two wall panels. One panel has connections for component video (YPbPr) and 2-channel audio, along with an HDMI jack. This is good enough for modern game consoles, such as the PS3 and the Wii. The other panel provides the necessary connections for a computer: a DE-15 connector (for VGA through SXGA) and an ethernet jack. We use this connection for showing movies and slide shows from a laptop, reminiscent of the "slide show evenings" our family had when I was a child.

I used black panels and inserts to fit in with the room decor. I opted to use the keystone system to build the panels exactly as I wanted. Keystone panels provide 2, 4, or 6 holes and a large collection of jacks to fill those holes. With this system it was easy to create what I needed. Since the DE-15 connector is too large to fit in a keystone hole, I searched and found a plate that has this connector pre-mounted with two keystone holes underneath (in black).

The automation system provides selections for each of these connectors. When selected, the system powers on the projector and the receiver, then sets the appropriate input on the receiver. The DE-15 connector bypasses the receiver entirely and is connected directly to the PC input on the projector. The automation system sets the projector's input accordingly but also selects the component input on the receiver so that the 2-channel audio jacks can be used for sound when this input is used.

Some time after I finished this project I turned my attention to the subwoofer. Unlike a conventional speaker, a subwoofer is a powered device, so its input is line-level via an RCA style jack. Subwoofers typically power on automatically when they sense something on the input, then power themselves off after a period of no signal. But powering on is not instantaneous: it can take up to a second before the subwoofer is ready to make noise. For most movies this arrangement is not a problem.

One night I was watching Breaker Morant and I noticed that the subwoofer turned itself off in the middle of the movie. Breaker Morant only has a 2.0 soundtrack and the subwoofer is used very little. The period of time between uses was enough for the subwoofer to shut off. But that meant a lag between when it received a signal and when it was ready, so some of the low level effect was lost. This simply would not do.

The Integra receiver provides three 12-volt triggers. A trigger is an output that can be used to tell another device when to power on. So I connected one of the triggers to the subwoofer. When the receiver turns on, it sends a signal on the trigger, the subwoofer turns on and stays on until the receiver shuts off.

Initially I ran this trigger wire the same way as the subwoofer wire: through a hole in the wall. But this seemed awfully untidy. I decided to clean this up a bit and added a 2-hole Keystone wall plate to hold one RCA jack (for the subwoofer signal) and one 3.5mm jack (for the trigger), all in black. It was easy to find the parts for this wall plate in white, but I had to do some serious Internet digging to find them all in black. This panel is so obviously useful that it really ought to be sold as a complete unit.

Today I have a clean front wall in my theater. Connecting a game console to the theater is easy, and the results are just as impressive as any movie.

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