The invention provides devices and methods for acoustically assessing the contents in a plurality of reservoirs. Each reservoir has a portion adapted to contain a fluid, and an acoustic radiation generator is positioned in acoustic coupling relationship to each of the reservoirs. Acoustic radiation generated by the acoustic radiation generator is transmitted through at least the portion of each reservoir to an analyzer. The analyzer is capable of analyzing a characteristic of the transmitted acoustic radiation and optionally correlating the characteristic to a property of the reservoirs' contents. The invention is particularly suited for assessing the contents of a plurality of reservoirs to allow for accuracy and control over the dispensing of fluids therefrom.