C# How to improve the note accuracy of my rhythm game??

[Joanne]

I am currently working on a rhythm game that has notes travelling from the top of the screen down to the bottom, where it reaches a button that when pressed triggers a hit. I have paired the game with background music. However I notice that as I play for a long duration of time, the notes do not collide with the buttons on the beat of the music anymore, and goes out of sync. Here is my code:

 

[Antero360]

I am currently working on a rhythm game that has notes travelling from the top of the screen down to the bottom, where it reaches a button that when pressed triggers a hit. I have paired the game with background music. However I notice that as I play for a long duration of time, the notes do not collide with the buttons on the beat of the music anymore, and goes out of sync. Here is my code:

Hi there,
A few questions:
1) In your start method, is the beatTempo supposed to be divided by 60f?
2) In your update method, inside the else, is that supposed to be subtracted?

I just want to make sure that is not an issue overall