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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

  1. 20100217: Hydrophone files initially made publicly available
  2. 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

For hydrophone data products only (audio and spectrogram data) on the hydrophone array devices only:
H1

This option will cause the search to return results for hydrophone channel H1 only. The hydrophone arrays consist of multiple hydrophones connected to a single data acquisition computer, which collects the data into single files that have multiple channels (nominally raw hydrophone array files, although other formats can handle multiple channels). Data products may be produced from these files on a per channel basis and returned as specified.

This is the default option.

Oceans 3.0 API filter: dpo_hydrophoneChannel=H1

File-name mode field

'H1' is added to the file-name when the hydrophone channel option is set to H1, i.e. IOS3HYDARR02_20111211T152404.000Z-spect-H1.pdf.

H2

This option will cause the search to return results for hydrophone channel H2 only.

Oceans 3.0 API filter: dpo_hydrophoneChannel=H2

File-name mode field

'H2' is added to the file-name when the hydrophone channel option is set to H2, i.e. IOS3HYDARR02_20111211T152404.000Z-spect-H2.png.

H3

This option will cause the search to return results for hydrophone channel H3 only.

Oceans 3.0 API filter: dpo_hydrophoneChannel=H3

File-name mode field

'H2' is added to the file-name when the hydrophone channel option is set to H3, i.e. IOS3HYDARR02_20120801T090939.000Z-H3.mp3.

All

This option will cause the search to return results for all available hydrophone channels.

Oceans 3.0 API filter: dpo_hydrophoneChannel=All

File-name mode field

'H1', 'H2', 'H3', etc are added to the file-name.

Hydrophone Data Diversion Mode

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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.

For WAV format data, the files will be accompanied by a calibration file. This file is a text file, comma delimited with one descriptive header row. It is named following the usual standard and ending with '-hydrophoneCalibration.txt'. The dateFrom / dateTo is taken from the calibration date range of the first sensitivity bin attribute. If a search extends over multiple calibrations, multiple files will be produced. A currently applicable calibration will produce a file named with a dateTo that is midnight tomorrow. Here is an example of the first few lines of a hydrophone calibration text file:

#Hydrophone calibration sensitivities. The file contains one header line followed by comma delimited data. First column is the centre frequency of each frequency bin(Hz). Second column is the sensitivity calibration for each bin (dB/uPa). Data is from device attributes: http://qaweb2.neptune.uvic.ca/DeviceListing?DeviceId=1230 . Device attribute HydrophoneSensitivityVectorPart1 last modified: 02-Dec-2015 20:59:52. File created: 29-Mar-2016 15:36:06.
1, -33.1853
2, -30.6233
3, -29.8957
4, -29.6103

 

 

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