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Aug 1, 2018

Apply a range frequency filter

1 comment


I'm trying to figure out how to apply frequency filtering to AudiouMoth firmware in order to record bats only. Something similar to the approach described in the Methods Ecol Evol paper where frequency filtering was applied to record cicada using a 8-14KHz range filtering. Apparently custom frequency setting is not discussed at Github Minimum Project Firmware.

Could the custom code used in the paper be shared?

All the best,


Aug 5, 2018

I suspect that there is not a lot of point to digital filtering in real time. If any intermodulation distortion was going to take place due to loud low frequency noises then this will already have happened by the time the digitisation has taken place. Unless you are doing other real time processing of the signal you might just as well record the raw digitised data and then apply any filtering to the audio files later. Audacity can be configured to apply a high pass filter to batches of files in a single process to simplify the task - we do this to all our recordings before making them publicly available through Figshare (according to the Open Data principle) in order to remove conversations during recording.

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