For hydrophone data products only (audio and spectrogram data):
Original Data
This option will cause the search to return results for original data only. Altered data is excluded. For security reasons, the military occasionally diverts seismic and acoustic data. Usually that data is returned, after a delay of 3 days to 2 months, but in an altered form. Diverted data is usually altered by band-pass filtering, often with decimation or resampling. In rare circumstances, diverted data is returned whole or is re-constituted from it's low-pass and high-pass components; this data will be returned by a search using the original data option. Data diversion is further explained in the data diversion page.
Low Pass Filtered
This option will cause the search to return results for diverted data that has been low pass filtered only. The file-name of low pass filtered data will an 'LPF' in the mode field: ICLISTENHF1234_20110101T000000Z-LPF.wav.
High Pass Filtered
This option will cause the search to return results for diverted data that has been high pass filtered only. The file-name of low pass filtered data will an 'HPF' in the mode field: ICLISTENHF1234_20110101T000000Z-HPF.wav.