How similar should a tune be to constitute theft of someone else's tune?

Question

i am a composer of hip hop songs. As opposed to rap songs, hip hop songs are very melodic by nature. now sometimes i get inspired by someone else's tune, or write my own tune and then find out someone wrote a similar tune too. When you look at melody there is:

• notes
• key
• sounds (or instrument)
• volume
• length of each note (which can be different between the notes)
• sequence of the notes (which note comes after which note)

1. My question is across these, how many things have to be different to show it is similar?

2. Also specific question about number of notes- lets say i have same sequence, almost same volume and length. how many notes before it becomes theft? 3? 5? 7?

I am choosing US because most of the hip hop songs are in the US. But i am in the UK. But I'm trying to make songs that work for the US too.

Answer 1

There is no real answer to this question. The analysis will always be qualitative, not quantitative. If your work sounds "too similar" to a protected work, it's at risk of being deemed an infringement.

There's no way to say exactly where the line will be drawn, as there are so many elements at play, any one of which could put you over the line.