Hello, I encountered some issues when checking my AudioMoth devices. I’m using AudioMoth primarily for bat detection, with a sampling rate set to 384kHz and the gain set to Med.
When I place two AudioMoth devices simultaneously and record at the same time, both devices appear to operate normally (indicators are correct, and files are created properly). However, upon review, at the same exact time, one of the devices detected bat calls (>40kHz), while the other did not. The AudioMoth that didn’t record the bat calls still has an audio file that can be played directly and includes clear human voices. In other words, everything seems correctly set up (the spectrogram even shows color in the high-frequency range, not just black). Why is one AudioMoth failing to record higher-frequency sounds?
I’ve already ruled out issues with the SD card (Sandisk Extreme 128G), battery level, and waterproof membrane, and the device has not been dropped. Are there any other
aspects I can improve?
The attached files are spectrogram of two detectors. Please let me know if you need any additional information to help clarify my issue.
Thank you for your help!
Hi Yunnn
I've had a problem with missing frequency bands with one of my new AudioMoths when placed in a case, I'm hoping that I have identified the reason for the poor performance in mine being due to raised solder blobs stopping the AudioMoth unit sitting flush with the membrane. Subsequent filing down of the solder blobs seems to have solved to problem. This might be worth investigating for your AudioMoth. I have just posted a description of the effect and my solution, see post titled "Missing frequencies bands in the recorded sound spectrum with AudioMoth placed in the official case."
Trevor Shepherd