Citrus College Near Space Balloon Project 2013-2014 Volume 1

To ensure redundancies, in the event the recorder in the balloon does not capture any sound, there will also be recording equipment on the ground. In a secluded area two types of microphones and a light meter will be set up. One of the microphones will be a shotgun microphone. This type of microphone has a small diaphragm which allows sound to be recorded with precision, and will record sound from the direction it is pointed. The second type of microphone is an omnidirectional stereo microphone. This microphone records sound in a cardioid shape. Hence, it will not record sound directly behind the microphone but will record sounds in all other directions. The advantage of using a shotgun and omnidirectional stereo microphone is that if any sound from the aurora borealis is recorded, the direction of the sound can be located- verifying whether or not the lights caused the sound. The two microphones will be connected to an AD/DA converter. An AD/DA converter takes the recorded sound and converts it to binary code. There will also be a light meter that will measure the intensity of the light emitted by the aurora borealis. This will verify a correlation between the aurora borealis and any unusual sound recorded. For example, if the light of the aurora borealis increases in intensity and a sound is recorded around that same time, there is a probable chance that those two occurrences are related or rely on one another. If any abnormal sounds that travel from the direction of the aurora borealis and while the lights are at their brightest, then it can be statistically proven that there is a correlation between the aurora borealis and the sound recorded. The files of sound recordings will be analyzed back at Citrus College from February through March. This will entail uploading the recordings to a software called Protools. This software is a digital audio workstation. The second step will be to utilize Protools to convert the sound recordings into waveform. Next, with the use of plugins and tools available in Protools, sounds that can be discarded will be separated from noises that are abnormal. Also, spectral analysis will also be employed. This process will determine the frequencies of every sound. This process will be helpful to identify infrasonic sounds, sounds below 20 hertz, and supersonic sounds, sounds above 20 kilohertz. Infrasonic and supersonic sounds are out of the hearing range of humans. Thus, it is possible that humans are incapable of hearing the sounds that supposedly occur during the aurora borealis. -? 8-?

Citrus College Near Space Balloon Project 2013-2014 Volume 1 | Page 8