Re: Help me out guys..
I have owned and played the 901 for about 18 months. I assume your talking about the forth line D. There are two things I found to clear up that. The first is to make sure your throat is open and not conscrited. If that does not work, play the D as usual but also depress the left hand D palm key. To check for a leak, play a normal D with octave key. Then play a second time using the left hand D palm key. There will be a change in tone but should not be a change in the note. If there is a change in the note, like being flat or sharp. Then you do have a leak.