failure: recognition of musical notes in Spanish

[Juankasp]

Hi, I have made a small online game to practice recognizing musical notes in Spanish, and practically all the notes are recognized well except the note "do". It breaks all the statistics and it is almost impossible for you to recognize it.
This detail makes the game almost unfeasible.
On the other hand, is it normal that it takes a little more than a second to recognize and execute the command? is there any way to speed up that second?

Thank you.