Friday we continued our perfect technology quest, this time focusing on audio. While we actually want the cameras to capture the video in an overlapping manner, so that we can track visitors from one spot to another and be able to see their faces no matter what angle they face, it turns out that the audio is a different matter. Due to the acoustics in the Center, if we’re not careful, a mic at the front desk will pick up voices 25 feet away at the wave tank, not only muddling the audio we want to hear from the front desk, but also perhaps turning on extra cameras and recording unrelated video.
In order to localize the audio to particular people and in order to understand speech clearly, we’ll use so-called near field recording (up-close to the speaker rather than capturing a whole room). We’ll also need to input multiple mics into certain cameras in order to have audio coverage with minimal wiring in the way of exhibits. Beyond that, though, was the question of what kind of pickup pattern we need – whether the mic records audio straight in front of it, in front and behind, or all around, for example.
With help from audio technicians from the main campus who were out to work the retirement of one NOAA research vessel and the welcoming of another, we discussed the ins-and-outs of particular shapes of recording areas. Probably our best bet in most cases will be a carotid, or heart-shaped, mic, which gets mostly what’s in front of the mic, but not in a straight line, and some of what’s behind the mic. The exact sizes of the patterns can often be tuned, which in our case again will be crucial as we begin to determine how visitors use particular exhibits, where they stand when they talk to one another, and especially how they might move up and down as they interact with people of different ages and heights.
As usual, one of our biggest challenges is trying to retrofit this recording equipment into an already built space, and a space built with weird angles, less-than-optimal acoustics, somewhat unpredictable speaker locations, and often loud but inconsistent ambient noise such as the 65-decibel running water in the touch pools. But hey, that’s why we’re trying it, to see if it’s even possible and beyond possible, helpful to our research.
