Portable instrumentation for the recording, analysis, and playback of infrasonic animal vocalizations

Abstract

Several bioacoustic experiments required an affordable system capable of field recording, real-time analysis, signal editing, and real-time playback of infrasonic animal vocalizations. The synthesis of several types of recording devices and signal processing software has resulted in the capacity to record infrasound and perform analysis even during rain, heat, and high humidity. Small portable microphones and recorders can record in the field from 3 Hz to 22 kHz. On-site analysis including real-time FFT, color spectrographic function, filtering, cross-correlation, and other functions can be facilitated with the use of any portable computer with 92 Mbytes RAM. Signal editing, including frequency, amplitude, and cut/paste can be accomplished with readily available music signal processing software. Real-time field playback from 10 Hz to 45 kHz can be acheived by using portable car audio speakers. This system was used for the real-time analysis of elephant vocalizations, which were edited and played back immediately during recording sessions. It has also been used in field research involving tiger, binturong, rhinoceros, and giraffe. Tigers and elephants appear to respond behaviorally to real-time playback of original and edited vocalizations. [Work supported by National Instruments, Momentum Data Systems, and Sonic Foundry.]