Manhattan University of Music professor and Experienced double bass participant Timothy Cobb teaching a bass lesson in the late 2000s. His bass includes a low C extension with a metal "machine" with buttons for playing the pitches over the extension. People aiming to be Specialist musicians, singers, composers, songwriters, music https://acheterdesvuesyoutube40382.blogacep.com/32424004/new-step-by-step-map-for-youtube