Hi, I'm working on a project that involves generating signals to a loudspeaker and measuring them on microphones. After I've run my VI (attached), I now find that the analog inputs from the microphones have the same frequency throughout (50Hz, which is the mains frequency), regardless of what the frequency of the loudspeakers are (I'm expecting the frequency of the microphones to be similar to that of the loudspeakers). I'm not sure what the problem might be. I think the microphones are working correctly as it does detect sound. They are normal tie-clip microphones and are battery charged. So I'm now wondering whether the problem might be in the method the DAQ devices were set up, or the input terminal configuration of the channels. I'm using a PCI 6229 device with 16 RSE input channels for the microphones. Another problem which I've observed (different from the above) is that when I set my VI to save data, the loudspeakers makes a 'pop' sound every second or so. It does not produce this sound when I don't turn it on, which is very odd. Thank you for any help on this.

Multifunction DAQ

Input frequency from microphones does not vary

Hi,

You're quite right, any FFT etc that you carry out will be unaffected by DC components anyway!

I'll have a look at that second post shortly and get back to you there.

Regards,

Tom

Applications Engineering, NI UK

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Multifunction DAQ

Input frequency from microphones does not vary

Re: Input frequency from microphones does not vary