Is the music from African born Americans or black Americans?

Generally, Americans of African descent. The music was borne out of Africa.

It is a history and timeline of African American music, starting in Africa, progressing to spirituals and gospel in slave times, ragtime and jazz in the early 20th century. Then it details the development of rock and roll from African American music influences and on to hip hop.

Both....

What's the difference of African American and black Americans?

Americans of African descent. Although, an area showcasing the start would be great! I don't remember seeing that...

There is some African music when you first enter the museum. But most is African American

African Americans