Louis Armstrong

Louis Armstrong played jazz trumpet, sang and acted for many years in America and all over the world.  He has a way of timing when to start a note that was the same when he played the trumpet, or when he sang.  

Questions

What are the sounds that Armstrong makes at the start and end of his notes? (singing and trumpet).

Hard

Armstrong's solos seem to float over the beat, always in time, but also always in his time.  How did this help him to be such a great improviser?