Currently working on a project that involves recording bat audio in urban environments. I had configured and flashed with some configs that seems to have worked in the past (from other posts), but I think the Issue I am having is related to the filtering. I did a test recording and it didn't really seem to filter anything out when I had set it to amplitude 20kHz -96kHz. For trigger duration I dont exactly remember what I did but I believe that it was at zero seconds which is definately an error and I'm not really sure what Amplitude durration means and if I should touch that when setting a filter.
I'll list my configurations for some context
Sample Rate: 192
Gain: Medium
Enable sleep/record cyclic recording: on
Sleep duration: 5 Seconds
Recording duration: 55 seconds
Schedule 7:00 pm - 12:00am
Trigger Type: Amplitude
Filter Type: Band (20khz - 96khz)
Minimum Trigger Duration: 0s
Amplitude Threshold:?
Could anyone provide some insight in which configuration settings I should have?
For some additional context, I mainly want to investigate bat biodiversity in urban environments and their feeding guilds for different sites with varying vegetation.
Hi, There are two types of filtering possible - one based on amplitude and one based on frequency response. The amplitude one is the easiest to configure. If you are recording bats, you can set a high pass filter to remove most low-frequency background sound and then set an amplitude threshold that triggers on the calls. With a sample rate of 192kHz, the settings below will work pretty well.
You'll get separate T.WAV files which can be expanded out to their full 9-minute 55-second length with the 'Expand AudioMoth T.WAV Files' option in the Confi App. The minimum trigger duration means that the AudioMoth will always record at least 5 seconds of audio on each trigger. This enables you to capture periods immediately after a loud call. The default setting of 0 will only capture the 32kB periods within which there is a trigger event. The frequency trigger is a bit more sensitive, but it harder to set up as it depends on the frequency of the call. The easiest way to set it up is to load an example into the AudioMoth Play app - https://play.openacousticdevices.info - where you can experiment with the settings and see the effect immediately.
You can also you the AudioMoth Play site to experiment with amplitude triggering and the effect of different filters. Just make a regular recording and then upload it to the app.
The application note presents more details of how to use this feature - https://github.com/OpenAcousticDevices/Application-Notes/blob/master/Using_AudioMoth_with_Filtered_and_Triggered_Recordings/Using_AudioMoth_with_Filtering_and_Triggered_Recordings.pdf Alex