Labview capture audio

Hello,

i wish to use Labview to capture the audio at my PC microphone,

I tried both sound-->acquire wizard

and also sound-->configure-->sound input read

both can produce sound wave, however the 1st second is flat line, then only audio wave comes in, i do not know why the 1st 1 second is flat always, is it something to do with windows driver?

i only interested at 100ms wave, but now i must wait until 1.1second then trim the 1second away. is there way to make soundwave available immediately after we run labivew to capture?

Thank you.