Problem with DeNoiser effect

Hi,

i have a poblem with the DeNoiser effect in Premiere Pro 6. I am using a couple of self made audio comments on a current movie project. To delete any disturbing noises in the audio tracks, i use the DeNoiser effect. Unfortunatly the effect does not work right from the beginning of the audio tracks. It takes something around a second before all disturbing noises are deleted and the audio recording sounds really clean. Any ideas what the problem is ? By the way .. the problem is also there after rendering the project.

Thanks and best wishes from geramyn Guido