Hello … I am new here and hope to put this question
in a proper place.
So I tried to use this sheet music of alouette to find the note names
for a music program.
I recognized the b behind the violine- and the bass-key that is meant
to lower a semitone.
But I only recognized differences in the output of my music program for
all the B-notes that had to be B-flat-notes to sound all right.
Would someone be willing to explain this to me?
Thank you very much.
Not a hundred percent sure I understand your question, but your “problem” could lie with the fact that you have German sheet music there. In the German system B stands for Bb in the English system. If it were B (in the English system), it would say H in the German system.
Maybe that helps a bit!?
Hi @Bruce, welcome to the forums! The “b” (flat) symbol is on the line of the “B” note in both the treble and bass clef. This means that any “B” note in the score is actually a “Bb” (B flat). All other notes are unaffected. Does this help?
Yes, very much. I am kind of beginner of sheet reading and the violine- and and bass-key
with their possible modifications put me in trouble to understand what is wirtten on the sheet.
if the b is only relevant for the line it is drawn on this ‘problem’ becomes now much clearer to me.
Thank you very much.
To make it very clear: there are only B-flats in the score you shared, no B naturals anywhere 
Yes … also the B-Notes that are drawn an ocatve above or below this flat sign line
in the beginning are to be considered.
And now my experiments helped me understanding music sheets a little better 
If someone is interested in Sonic PI my result of this sheet is published on
in-thread forum there under the Topic : [Blue Monday full intro version]
As everyone has described, yes. If you see flats (b) or sharps (#) at the beginning of the music - before the time signature - the notes that the flats and sharps are written on (the B in the case of your example) will be altered in all octaves, in all instances for the entire piece.
It’s called a key signature, and is short hand so that the composer doesn’t have to write in the symbol in the notation each time it appears.
and since I didn’t see it mentioned, the key of that piece is F Major which is why you also see so many of the bars starting/ending with an F. C is also very prevalent which is the 5th of F.
