Using NI 9234 to acquire audio from normal microphones

[Gilberto_Garza]

I am using a cRIO9076 with several NI9234 to acquire sound from different channels simultaneously. I have normal microphones connected to the NI9234 BNCs, I have tested the termination of this BNC with my computer and I receive a very clear signal of the audio.

The problem that I have is that when I acquire from the cRIO and then when I convert to audio with the "Play Waveform" subvi, I receive a lot of noise. I even connected the BNC to the cRIO and there I connected a two wire cable to a 3.5mm audio connector to check if in the computer if I received the noise, but the sound was clear.

I would like to know if the NI 9234 can be used for acquire sound from normal microphones, and if so, which configuration of AI channel do I have to use (AC/DC couple, IEPE).

Best regards,

Gilberto Garza

[Henrik_Volkers]

What is a normal microphone?    (The 'normal' microphones I know are for example B&K type 4144 ones and need about 200V bias 😄 )

Common mics you can plug into your PC-MIC port are usually ECM types and the MIC port provides:

1. - a 2.?? Volt supply

2. a preamplifier