Acoustic Frequency Apparatus are equipped with a wrench for rotating the adjusting screw three and a gable. Twisted steel wire, through the wire dynamometer to observe how much tension, plucked the steel wire, will be issued a high tone. (can also be used to increase the size and bearing steel wire vibration propagation.)
Acoustic Frequency Apparatus
Gelsonlab HSPA-001 Acoustic Frequency Apparatus for Educational use
Our ancient people have discovered this situation, such as the ancient Chinese string instrument, and the Western string instrument is the results of this discovery.