Hi. I dont have any experience with these vi's but I am guessing the 1ms waits may be the problem. Take them out of both loops. The top loop will then be timed by the sound acquisition and the bottom loop will wait for data at the dequeue function. I suspect the 1ms delays add up and you miss a **bleep** of data each second or so. Try it and see what happens, post back when you do.
Michael
Michael