I am not sure. Maybe the power supply of your laptop, which in turn powers the Bela over USB, is not the best? Can you try powering the board with some other means? Like, a mobile phone charger, a battery or another computer? You can run the Bela patch at boot by setting it from the configuration tab of the IDE. Also, a recording of the noise you hear may help (you can use the code below to log your audio input to disk, based on 07-DataLogging/logging_sensor
(see there for more details) :
#include <Bela.h>
#include <WriteFile.h>
WriteFile file1;
bool setup(BelaContext *context, void *userData)
{
file1.init("out.bin"); //set the file name to write to
file1.setFileType(kBinary);
return true;
}
void render(BelaContext *context, void *userData)
{
for(unsigned int n = 0; n < context->audioFrames; ++n) {
for(unsigned int c = 0; c < context->audioInChannels; ++c) {
file1.log(audioRead(context, n, c));
}
}
}