Characterizing the absolute sound levels of ambient noise in a water tank

The underwater acoustic measurement tank used at Brigham Young University is affected by several external sound sources which, although easily identified or hypothesized about on a superficial level, must be investigated in order to determine their specific effects on data collection. Therefore, our goal is to characterize the absolute sound levels of these external acoustic sources. The measurements are conducted using B&K and TC4038 hydrophones. Data are collected over frequency bands within the “flat” range of these hydrophones, facilitating the consistent identification of ambient sounds across several bands. Measurements are taken at various points of the tank in order to determine to what extent tank location affects the ambient sound. Data in Volts are converted to Pascals by applying sensitivity values. To evaluate the accuracy of levels obtained, the same method is applied to the signal from a known source and compared to the levels obtained via a deconvolution approach. The conclusions of this study are applicable in obtaining sound levels in our own tank and in other environments (e.g., aquariums). Undergraduate Research supported by the College of Physical and Mathematical Sciences, Brigham Young University