Hi Steve,
No really, it is audio noise! there is obviously some underlying electrical noise, which the designer has spent a lot of time reducing. If you look at.
https://cdn.bats.org.uk/uploads/pdf/Res ... 1658090442
He wrote a very detailed article about it's design, mostly about how he reduced the electrical noise, because of the 250x gain required to get the microphone signal strong enough to record.
On his web site about building your own he also says:-
"Recommended micro SD card :
SanDisk Extreme 32GB. Note : Extreme, not Ultra. These cards were recommended to me by the AudioMoth team after a lot of research on their side, and having tried them they really are the best. Fast, reliable, and low electrical / acoustic noise. Yes, SD card actually generate sound when in operation, and the microphone will pick that up and lead to acoustic artifacts on your recordings."
As I said it definately got worse when I put it inside a plastic bag? I initially thought it was being caused by a line of site mobile mast, but putting it in a tin hat made no difference, then I found the reference to SD audible noise and tested that theory and sure enough it made a difference.
Anyway, no I have not found any support forums, for it, yet, hopefully in the future.
Regards Kevin.
Here are 2 recordings, one in free air, the other just in a plastic bag, I've increased the on screen gain and contrast to make it more obvious, but both recording were otherwise done with identical settings. Clearly the SD card itself will also have an effect, I have tested a few I had and there is a marked difference, in both electrical and acoustic noise.
No really, it is audio noise! there is obviously some underlying electrical noise, which the designer has spent a lot of time reducing. If you look at.
https://cdn.bats.org.uk/uploads/pdf/Res ... 1658090442
He wrote a very detailed article about it's design, mostly about how he reduced the electrical noise, because of the 250x gain required to get the microphone signal strong enough to record.
On his web site about building your own he also says:-
"Recommended micro SD card :
SanDisk Extreme 32GB. Note : Extreme, not Ultra. These cards were recommended to me by the AudioMoth team after a lot of research on their side, and having tried them they really are the best. Fast, reliable, and low electrical / acoustic noise. Yes, SD card actually generate sound when in operation, and the microphone will pick that up and lead to acoustic artifacts on your recordings."
As I said it definately got worse when I put it inside a plastic bag? I initially thought it was being caused by a line of site mobile mast, but putting it in a tin hat made no difference, then I found the reference to SD audible noise and tested that theory and sure enough it made a difference.
Anyway, no I have not found any support forums, for it, yet, hopefully in the future.
Regards Kevin.
Here are 2 recordings, one in free air, the other just in a plastic bag, I've increased the on screen gain and contrast to make it more obvious, but both recording were otherwise done with identical settings. Clearly the SD card itself will also have an effect, I have tested a few I had and there is a marked difference, in both electrical and acoustic noise.
Statistics: Posted by bleep42 — Sun Aug 04, 2024 3:49 pm