I just purchased a new LA Sax straight alto and there is something odd about it. Low and middle D are flat and I have tried all kinds of things but nothing has fixed it. The only solution so far is to add the low C# key as a vent which brings it right up to pitch. Has anyone evey heard of this with LA Sax or straight altos. I do something similiar on my bassoon never thought about it on a sax then I tried it and success.