So I have a solo in a band song, and I need to trill from an a flat to a b flat (low). I'm having trouble with it and my band director said to just practice, but nothing's working. Any ideas?

Are you using a trill fingering? I believe the trill fingering is finger a low b flat then lift up your middle finger on your left hand (A key) OR lift up both middle and ring fingers (G and A key) and trill those, whichever you find easiest.

*sorry meant finger a low a flat to trill up to a b flat

Use your alternate B flat fingering (left first finger and left thumb on first thumb key) so you dont have to worry about lifting that other finger (right index). It works. I had to do the same thing.

-Good luck(:

the trill fingering that tends to sound the most in tune, and often the easiest, is just use the thumb Bb and trill to Ab...I have found this to be the case after teaching this trill to several hundred students over the years