Dear, I’m analysing HydroMoth data using PAMGuard and I need some parameters related to the device calibration.
Do you know which values I should put in the Audio Data Acquisition module of PAMGuard concerning the Peak to peak voltage range and the Preamplifier gain?
I have used those ones, but I don’t know if these are fully correct:
The peak to peak voltage range: 2.000V
Preamplifier gain: 0.0 dB
I have used for my recording with HydroMoth a Sample rate of 250000 Hz and a Medium-High Gain.
Many thanks for your help,
Lydia
Hi Alex, very useful. Many thanks for your help
For HydroMoth the signal from the microphone goes to an external amplifier which is set to a gain of x11. So, a 10mV peak-to-peak signal coming out of the microphone is turned into a 110mV peak-to-peak signal which then goes into the software-controlled gain stage. With the default medium gain setting, this is then turned into a 0.110 x 15 = 1.65 V peak-to-peak going into the ADC. The ADC has a 2.5V range (-1.25V to +1.25V), so the original 10mV signal becomes a digital signal with a range of 1.65 / 2.5 = 0.66 of full range (e.g. -0.66 to +0.66).
The full table of gain settings is in this application note:
https://github.com/OpenAcousticDevices/Application-Notes/blob/master/Configuring_the_AudioMoth_USB_Microphone_from_the_Command_Line/Configuring_the_AudioMoth_USB_Microphone_from_the_Command_Line.pdf
The standard gain of 11 x 15, which is x165 in voltage terms, is 20 x log_10 (165) = 44.35 dB.
Alex