การปรับตั้งแท่นยกด้วยกล่องความต้านทานและค้อน

This is a set of 2 tuning forks called Sympathetic Tuning Forks. Each of the large Aluminum Alloy tuning forks is hand ground to high accuracy and has a frequency of 440 Hz (hertz=cycles / second ). They have been carefully matched and individually electronically tuned for tonal clarity to their designated or physical range as marked. Each fork is mounted on an individually adjusted resonance box. They have identical frequencies, so that when the openings in the boxes are facing each other, either fork will respond in resonance to the vibrations of the other. Forks measure 6 1/2" long.