Interactive Bioacoustic Spectrogram Visualizer
Inspect time-domain waveforms and Short-Time Fourier Transform (STFT) time-frequency representations of marine hydrophone recordings. Analyze whistle fundamental contours, harmonics, and click pulses directly in your browser.
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Bioacoustic Spectral Reference & Scientific Boundaries
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Reducing playback speed (0.25×–0.75×) stretches time and lowers frequency proportionally (f' = f × rate). Slowing down an audio stream does not recover unrecorded ultrasonic frequencies (e.g. click centroids at 110–130 kHz) that were not digitized by the hydrophone recorder.
Acoustic Class Demarcations (Species-Specific Context)
Continuous, narrowband frequency-modulated signals used for social cohesion and individual identity.
- Bottlenose (T. truncatus): Fundamental contours typically span ~4–20 kHz (inflection points to ~24 kHz; Sayigh et al., 1990; Janik & Sayigh, 2013).
- Atlantic spotted (S. frontalis): Fundamentals typically span ~6–18 kHz (min ~5 kHz, max to ~21 kHz; Herzing, 1996).
- Harmonic overtones: Frequently extend above 20 kHz into broadband ultrasonic bands (>40–100 kHz; Lammers, Au, & Herzing, 2003).
High-frequency transient impulses for echolocation and dense packet pulses for social signaling.
- Echolocation Clicks: Transient impulses (40–70 µs) with bimodal spectral peaks typically at 40–50 kHz and 110–130 kHz (Au, 1993; Au & Hastings, 2008).
- Burst-Pulse Packets: Pulse repetition rates of 200 to >2,000 clicks/sec (inter-pulse intervals <5 ms). Psychoacoustically perceived as squawks/cries; appear on spectrograms as harmonic sidebands spaced at the pulse repetition rate (Overstrom, 1983; Herzing, 1996).
*Important biological qualification: Acoustic parameters vary systematically across species, populations, water depth, and behavioral state. Published ranges represent documented empirical observations rather than universal odontocete constraints.