AudioMoth Filter Playground

Select an AudioMoth WAV file up to 60 seconds in length:
Loading
Waveform
Spectrogram
8 16 32 48 96 192 250 384
Sample rate (kHz):
None Amplitude Frequency
Trigger type:
None Low Band High
Filter type:
0kHz
24kHz
0 1 2 5 10 15 30 60
Minimum trigger duration (s):
0.001%
100%
16 32 64 128 256 512 1024
Window length (samples):
0kHz
24kHz
0 1 2 5 10 15 30 60
Minimum trigger duration (s):
0.001%
100%

Instructions

The AudioMoth Filter Playground allows you to explore filtering and thresholding on existing AudioMoth WAV files before applying them in the files.

Select a file recorded on an AudioMoth which is up to 60 seconds in length. Longer files, up to 43.9 MB, will still load but will be truncated. Once the file has loaded, you can navigate through your recording using the buttons above the plot, or by clicking and dragging to select the area you wish to see in detail. You can also double click on either plot to zoom in and centre on specific features of interest.

Add a low, high, or band pass filter using the controls on the right; selecting a radio button besides "None" to add a filter and then dragging the sliders to set the required filter frequency. The plots update in real time to show the effect of the filter.

Apply an amplitude threshold or frequency trigger by clicking the corresponding radio button on the right and then dragging the slider to set the threshold. The threshold will be drawn onto the waveform plot to show you which parts of the signal will trigger. You can change the units used to display this threshold using the drop-down menu at the top left of the plots. Once a threshold has been set, the plot will automatically grey out parts of the recording which fall below the threshold.

Selecting the frequency trigger will change the waveform to a frequency response plot. Use the radio buttons and slider to set the frequency band shown on this plot. Once you've chosen a band, drag the lower slider to set the frequency response threshold.

Selecting either the amplitude threshold or no threshold will allow you to add a low, high, or band pass filter; tick the checkbox to enable the filter and then drag the sliders to set the required filter frequency. The plots update in real time to show the effect of the filter.

Once you are happy with the filter and amplitude threshold settings, click Export Configuration to download a .config which can be loaded in the AudioMoth Configuration App (version 1.6.0 onwards).

You can use the controls beneath the plots to export WAV sound files, PNG, JPG, and PDF images, and MP4 videos of your AudioMoth recordings.

Example files

You can use these example files to explore settings if you do not currently have an AudioMoth file to use.

FAQs

Why won't my file load?
Currently, the AudioMoth Filter Playground will only load 16-bit PCM WAV files, recorded at either 44100 Hz (a standard sample rate supported by most microphones), or one of the sample rates supported by AudioMoth (8, 16, 32, 48, 96, 192, 250, and 384 kHz). If you load a file at 44100 Hz it will be automatically resampled to 48 kHz.
How do I reduce the size of my recordings?
Recordings can be no longer than 60 seconds and must be split into shorter files if they exceed this limit. In order to remain readable by the AudioMoth Filter Playground, recordings must be split using the Split function found in the AudioMoth Configuration App. Select "File" and then "Split AudioMoth WAV Recordings" to access it.
What is "amplitude threshold triggered recording"?
Amplitude threshold triggered recording is a recording mode where an AudioMoth will only collect samples when their amplitude exceeds a certain value. Once a threshold has been selected, these samples are saved to SD card, as well as the lengths of the gaps between each acoustic event.
What is "frequency triggered recording"?
Frequency triggered recording is a recording mode where an AudioMoth will only collect samples when the response of a chosen frequency band exceeds a certain value. Once a threshold has been selected, these samples are saved to SD card, as well as the lengths of the gaps between each acoustic event.
What does "window length" change when configuring a frequency trigger?
The window length controls the width of the frequency band which the threshold is applied to. The lower the window length, the wider the band. The size and position of the band is displayed on the spectrogram plot when the frequency trigger is selected.
What changes when I set a minimum trigger duration?
Selecting a minimum trigger duration will make sure that all triggered recordings are at least this length, continuing to collect samples even after a triggered event has ended. This is useful for situations such as detecting bat calls, where the initial impulse can trigger a recording and the quieter tail of the sound is also required.
How do I zoom into a specific section of my recording?
You can navigate through your recording using the buttons above the plot, or move to a specific part by clicking and dragging or double clicking on either plot to highlight the area you wish to see in detail.