I realized that music was an important part of the migration, and certainly an important part of its impact on America. When acoustic musicians went North from Mississippi to Chicago, and plugged their guitars into the wall and started playing electric blues - that's one of the foundations of rock 'n roll of global pop music, actually. While certainly original, the effect is also somewhat jarring. So as a device to avoid some narration, the newsreels were created. Historians are concerned by that, but we make it clear that these are simulated newsreels, not genuine artifacts.
Most regular viewers seem to think it's pretty entertaining.