Hi Leprachaun,
It most likely is a minor leak in your D key and the pad is just not seating properly. Take a close look at it and see if you can see any leaks in it. I would have it checked out. Sometimes, some brands of piccolos are harder to produce a clear strong sound in the lowest register. The Jupiters in my experience with them have been pretty good though. Good luck with it.

Thanks for that Kara I`ll look at it today.