Care and Maintenance of a Marimba
Care and maintenance of the tone plate suspension cords

The tone plates of a marimba are suspended from cords. The tension of these cords also needs to be adjusted. If the cords are too taut, then the tone plates will rebound too much when struck. If, instead, the cords are too loose, then the cords will absorb the vibrations, making the sound project poorly from the instrument.

To adjust the tension of the tone plate suspension cords, alter the length of the cords and the locations of the knots with the suspension-cord-tightening portion and the springs on the bass side.
It should be acceptable if there is an adequate amount of elasticity when the cord is pushed down with a finger while connected to the springs.
If a cord is starting to fray, replace it as soon as possible.

The metal fixtures that receive the tone plate suspension cords are called bar-posts. These fixtures can bend after repeated transporting of the instrument.
If the bar-posts are bent, then it will interfere with the vibrations of the tone plates, so always check whether the bar-posts are bent before playing.