Audio Data
Audio data is primarily produced by hydrophones (underwater microphones). A number of hydrophones are producing audio files with sounds at a wide range of frequencies, having applications in seismology, marine mammal studies, ship noise and more.
Given the sensitive nature of hydrophone data, the military has authority to filter out sensitive frequencies or divert the data entirely, as required. When filtering occurs, the file-name is appended with 'LPF' or 'HPF' for high-pass or low-pass filtering. Often, the military diverted data will be returned at a later date, much of it modified from the original data, see here for more information on the diversion of hydrophone and seismometer data.
For hydrophones located on low-bandwidth observatories (Cambridge Bay, Brentwood Bay, etc), hydrophone audio files may not be available. In this case, any missing audio data is stored on site to be retrieved yearly, while the observatory will upload the spectrogram files as they are much smaller.
When requested format of audio data already exists in the archive, the search will complete immediately, otherwise some processing will occur to convert the formats. Processing times vary, but in general, expect it would take approximately 15 seconds to process one 5 minute file, so one hour to process a day's worth of data.
Revision History
- 20100217: Hydrophone files initially made publicly available
- 20130123: searches handled by matlab search to process data on the fly if needed; all formats made available to all devices
Data Product Options
Hydrophone Channel
Hydrophone Data Diversion Mode
Format
Hydrophone data is available in WAV and MP3 audio files. For normal hydrophones, WAV files are the base data type, for hydrophone arrays, HYD files are the base data type. MP3s are generated from WAV files and are stored in the archive or may be generated on the fly.
Discussion
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