Crossing noises are a common problem in playing the bagpipe. They are false notes created between top hand notes and bottom hand notes when the hands open and close in the wrong sequence. For example: The first and most popular crossing noise happens between D and E. It happens because we start on D, we close the bottom hand playing a low G and then open our pinky and our E finger to finally play the E.
Years ago, Bruce Gandy published a series of exercises in the EUSPBA magazine, "Voice". These were exercises meant to help eliminate crossing noises. However, the exercises themselves will not solve the problem unless you know why crossing noises exist.
Let's go back to the D & E positions. There are two transition choices available to you, the player. One choice, as shown below, is the right choice and the other is the wrong choice. As a crossing noise is a "false note", the wrong choice will insert a low G between the two positions. Choosing the right transition as shown below will solve this problem.
Because this is about coordination, I have found that it is helpful to talk your way through the positions until you are fluent in their execution. Sometimes the fingers don't do what they are supposed to do unless your brain understands why. As you move from one interval to the next, the common thread through all of these is to lead with the hand in the direction which you are going. For example: If you are going up, the top hand opens first followed by the bottom hand closing. If you are coming down, the bottom hand opens first followed by the top hand closing. If you apply this formula between intervals and talk your way through the coordination, you will not have a crossing noise problem. Some people might just have perfect synchronization, most people don't. There will always be some delay between hands opening and closing. It is better to side on the right sequence. It just takes practice.
Gary Guth is a professional bagpiper with over 45 years of playing experience and has been teaching bagpipes full time for the last 20 years. He has written "Bagpipes For Beginners", "the Bagpipe Hymnal", and " A Piper's Christmas".