Move the cursor over the image to toggle between low-resolution and high-resolution sonograms.

Low-resolution sonograms, as processed by zero-crossing, discard amplitude and harmonic information, and only display the sound component with the greatest amplitude (typically, but not always, the fundamental). When processed in this way, identical notes played by a piano and a violin appear indistinguishable. However, the characteristics that make them sound different to our ears are contained in the amplitude and harmonics, and high-resolution sonogram processing reveals those characteristics.

Note how the maximum amplitude (displayed as red) occurs at the beginning of the piano note, after the hammer strikes the string, then the amplitude trails off. For the violin, the maximum amplitude occurs in the middle of the note, and the harmonics are richer and more pronounced.

Just as in this example, bats also vary the amplitude allocation and harmonic structure of within their calls. High-resolution sonograms processed with SonoBat software can reveal those attributes and aid in discriminating species and other subtle differences of bat echolocation calls. And SonoBat makes it easy to do this with an intuitive point and click interface.

Until recently, high-resolution full spectrum acoustic analysis has remained out of reach to most users because of the high-end hardware requirements. However, today's generation of Pentium® laptops and G3 PowerBooks® with multi-gigabyte hard drives and high RAM capacities bring the potential of high-end acoustic processing to a wider audience. And SonoBat makes it a reality. It is no longer necessary to sacrifice essential acoustic information to enable smaller file sizes and avoid crippling a CPU.