SynSing: open-source MATLAB code for generating synthetic signals in studies of animal acoustic communication

Synthetic, computer-generated signals are widely used in playback studies of animal acoustic communication. Depending on the goals of the experimenter, they can offer several significant advantages over playbacks of recordings of edited or unedited natural signals. However, there are few ?off the shelf? software options for the bioacoustician interested in synthesizing signals that combine ease of use with versatility. Here, we introduce SynSing, a free, open-source graphical user interface (GUI) for generating synthetic acoustic and seismic signals in MATLAB for use in playback studies of animal acoustic communication. Following a brief overview of the GUI, we describe how users can specify a variety of spectral properties (e.g., fundamental frequency, relative amplitudes and starting phases of harmonic and inharmonic components, frequency modulation) and temporal properties (e.g., pulse, note, or call duration and rate, onset and offset characteristics of amplitude envelopes) to generate individual signals or long sequences of repeated signals. We demonstrate SynSing?s versatility by reconstructing synthetic signals from published studies of several frogs, a field cricket, a katydid, a grasshopper, and a spider. We also provide worked examples of simple birdsong, as well as pure tones, linear frequency modulated sweeps, and noise.