This is because the body of the cello acts as a baffle, reinforcing sound wave at all frequencies above that at which the width of the cello equals one wavelength. Than means that most of the reinforcing overtones as well as the highest of the fundamentals are compressed to the front of the cello from about the pitch a5 up. It's the same mechanism whereby we increase the projection of our voices by cupping out hands to the sides of our mouths to shout.
This is because the body of the cello acts as a baffle, reinforcing sound wave at all frequencies above that at which the width of the cello equals one wavelength. Than means that most of the reinforcing overtones as well as the highest of the fundamentals are compressed to the front of the cello from about the pitch a5 up. It's the same mechanism whereby we increase the projection of our voices by cupping out hands to the sides of our mouths to shout.