Location: Case laundry room is in the Northeast corner of 1st floor case dorm. It is the only laundry room in the dorm. The room has one door and one window facing Case courtyard. The room is rectangular, with four washers and four dryers lined up along the two longer sides. For this recording, the ballon was placed in the Southwest corner of the room. The recorder was placed on the 3rd washer away from the wall, approximately 5 ft away from the balloon. The recording was done when no washer or dryer was operating. Setup of the recording illustrated in the figure below:
30 dB decay: 0.2212s
50 dB decay: 0.4632s
60 dB decay: 0.8114s
decay to background level: 0.9472s
Peak Intensity: 81.79 dB
Bottom Intensity: 15.81 dB @ 1.6118s
Acoustic Description: The laundry room is an enclosed space with acoustically interesting objects such as full/half-full detergent bottles and sheet metals (found on washers and dryers). The nature of this room gives it relatively damp air that absorbs sound waves and minimizes reverberation. Immediately after the balloon pops, there was audible resonance produced by the sheet metals and/or the plastic bottles; then both the pop and its resonance decreases at a rate that is surprisingly rapid for such a confined space — sounds die off almost as quickly as they would on an outdoor field. The rate of the sound’s decay and the absence of strong echo suggest that the sound vibrations are trapped between the detergent boxes, absorbed by the moisture in the air, or converted to mechanical vibrations of the sheet metals on washers and dryers. The spectrogram shows a persistent, low frequencies sound after the pop (slightly above 30Hz), which might correspond to the vibration of the sheet metals after they receive the shock; however, without further testing we cannot draw definite conclusion on what caused the post-pop low frequency sound.