I finally got to help out at a fireworks shoot this weekend. It was called Summer Blast at Centerra. The shoot certainly was a blast, however since it was un-seasonably cold and rainy so it didn’t seem much like summer. Due to work I missed out on the show setup, but did get to partake in the pre show BBQ, watch the fireworks, and help with the cleanup.
My lovely wife and I showed up for the BBQ around six pm. It started raining as soon as I got a plate full of food. After the ground got good and wet we found that the field where we were standing is made up of approximately 10% scrub grass, and 90% clay. When the rain made contact with the clay it created an interesting layer of glue over dry ground. For each step we took a layer was deposited on our shoes increasing everyone’s height by about a half inch. As you can imagine this makes it difficult to move more than a few steps before you get all wobbly… Then you have to stop and shake the collected goop from your boots. Due to the rain and cold, most of the pyros put on their fire fighter turn outs. Soon the entire crew looked like drunken firefighters stomping on invisible field mice, and then stopping periodically to do the hokey-pokey.
The show was to begin at 9:30. Since this show was entirely computer controlled, and since there was not a single flammable object with in a square mile of so, the pyro crew had absolutely nothing to do. So we set up camp chairs on the hill above the mortar field and sat back to enjoy the show. The rain stopped about a half an hour before the first mortar tube sent its payload skyward. It was a great show.
I took some video and found out something interesting that I didn’t notice during the show. The sound wasn’t delayed. At least not much.
One of my pet peeves with many movies is the fact that loud noises (Explosions) usually do not follow the physics of sound. In most movies the sound of an explosion reaches the listener at the same instant as the explosion regardless of distance. This is also quite prevalent in movies with thunderstorms. In real life this is not the case, the speed of sound is just over 1000 feet per second. Usually the audience of a fireworks show is about a half mile away, so it should take the sound about two and a half seconds to reach them after the firework goes off.
I was a bit closer to the show. On the video it seemed that the sound was instantaneous. To me this was way cooler than a delayed effect. So, I guess I can understand a bit about why the movie sound editors clip out the delay. That said I still feel that movies should use the speed of sound delay for dramatic effect. Especially when an explosion happens behind the movie star, that way I can see him or her jump out of their skin. Their expression would be priceless.