Data for: Visualization of acoustic waves in air and subsequent audio recovery with a high-speed schlieren imaging system (Harvey et al.)
This depository contains video files obtained from high-speed schlieren imaging of acoustic waves propagating through air, produced by a speaker. For each video (.avi format), the start of the name corresponds to the frequency of the wave (if a sine wave) or the frequency of its fundamental harmonic (if a square wave). This ranges from 110 Hz to 40 kHz. The next part of the filename corresponds to the type of waveform sent from the function generator to drive the speaker, either a square wave ('sq1') or a sine wave ('sine1'); it should be noted that the actual audio output was limited by the frequency response of the speaker (which falls off sharply around 40 kHz), so a 'square' wave at 20 kHz will in practice be very similar to a sine wave. The last part of the filename describes the parameter changed for each trial. For the majority of videos, this describes the SPL of the speaker output, which falls in the range of 75 dB (for a 40 kHz sine wave) to 120 dB (for frequencies between 220 Hz and 15 kHz). For other videos, this describes a parameter of imaging: either frame rate (in frames per second x1000, 'kfps'), exposure (microseconds, 'us'). Files ending with '31kfps' have been imaged using a different camera position, to optimise the spatial resolution of the image. Each .avi video file is accompanied by a .cih file similarly named; this contains metadata from the high-speed camera. When read as a text file, imaging parameters can be inspected.