Request for info on A/V, Scoring, etc software

[Kevin Sevcik]

A little more random info. I'm fairly sure the scoring software interfaces with a custom PLC system developed by Hatch Technologies that acutally does all the lights etc on the field. The on screen displays are indeed a custom flash animation running on a computer that feeds its video signal and sound into the A/V system. All the flash animations are chroma keyed (think green screens) and overlayed over the main video feed. The video feed itself it typically provided by a few cameramen. A production guy manages the cameramen over headsets to get good shots and handles the transitions between cameras, powerpoints, etc. The production crew also handles the mics, lights, etc.

The DJ is actually mostly seperate from this whole system, simply giving the AV crew a music feed that they work into things.

For display purposes, the three options seem to be projectors, plasma displays, and those big LED arrays at the Champs. The projectors are mostly used at regionals where lighting is more easily controlled. I've usually seen some pretty big projectors for the big screens. I'd guess upwards of 10K lumens. And they're double stacked to get more brightness. Projectors give you a relatively cheap big image, but they're prone to getting washed out by lights hitting the screen. The plasmas were used at Lone Star for pit displays. These gave a much smaller image, but weren't washed out in the bright pit area. The LED arrays are awfully expensive but give you a big bright image that isn't prone to being washed out.

For anyone that's really curious, big systems like this are notoriously hard to set up in arenas and such. The biggest problem you run in to is ground loops. AV equipment bases all of its signals off a ground voltage level. As long as all the disparate pieces are using the same ground, things are fine. In large systems, you can have equipment on different circuits and different ground voltage levels. More specifically, you get a large loop of wire when the ground wire connects two pieces of equipment that are also connected on the same ground wire on the electrical outlet. These loops can build up current and either fry equipment in the worst case, or put a 60Hz hum into the A/V signal. This shows up as a loud humming, or a big white bar in a video. The solutions are numerous, ranging from the cheap solution of cutting the ground from the power cable for a quick fix, to large transformers tuned to 60Hz, to fancy opto-isolators that electrically insulate the two pieces from each other.

Yeah. Surely more info than you wanted, but I did work at an AV company for quite some time, so.....