Extreme and destructive testing:

（1） Low temperature and low humidity: Place the violin diagonally on the hot air outlet of the vertical air conditioner, align a sound hole with the hot air, and blow for half an hour. While the violin is very dry, immediately put it into a sturdy supermarket food plastic bag and place it in the freezer of the refrigerator at a temperature of minus 18 degrees Celsius. Two hours later, take it out to see the results and immediately test the sound.

Xiaofang: Externally, nothing happened. The overall tone color has not changed significantly. Still mediocre bass and flat midrange. The high notes are slightly stiff.

Beijing: The panel, back panel, and side panel are all fine. But the tone has changed, overall it seems to have become a bit stiff, and the natural feeling of vibration seems to have decreased a bit. The bass still has charm, but it lacks richness even more; The midrange sound is the same, but the empty can sound of the A-string seems more pronounced when using bow weight; The high notes are still clear and bright, but feel a bit hard.

Result: Unfortunately, I feel that the temperature difference between the refrigerator and the outside temperature in winter is not large enough. I plan to conduct the experiment again during the yellow mold days in summer when the temperature is high (around 40) and the humidity is high (around 90%).

Analysis: Under low temperature and low humidity conditions, the violin board and accessories will shrink and dry, generating a contractive internal stress that destroys the natural vibration of the violin, resulting in a tight and hard sound. Under severe low temperature and low humidity conditions, the shrinkage is extreme, exceeding the tensile strength of the wood fibers, causing some of the wood fibers to tear off and the piano board to crack.

（2） High temperature and high humidity: Put the violin into a sturdy black garbage plastic bag and close the bag tightly. Put water into the pressure cooker, boil steam, remove the pressure control cap, let the steam rush out from the small hole at the top, then put the garbage bag mouth on the small hole, let the steam pour into the garbage bag containing the violin, and then tie the bag mouth. It is estimated that the humidity inside will reach over 95%. Place the garbage bag containing the violin filled with steam in a large foot basin filled with hot water, and regularly heat the water to maintain a temperature of around 50 degrees Celsius. The hand test may be slightly hot. Two hours later, take it out to see the results and immediately test the sound.