What happened when strings loosened and sound column of violin fell off?
When you loosen all strings on violin, violin's sound stand also drops, then you should notice that violin's sound stand is too short. The cause of a short sound column may be too strong a change in humidity of weather. When weather is too humid, body of piano expands and sound column becomes relatively short.
Another reason is that these new violins have been used for a period of time and four strings are under continuous pressure, which can also very easily cause a slight deformation of violin body and a shortening of sound column. At present, it is absolutely necessary to find a professional technician to make an appropriate length speaker to replace a speaker that is too short. A short sound column does not support body of piano strongly enough, and sound of piano will be muffled, weak and uncertain.
Note to check position of top wing of sonic hole on right, which can help you determine if length of sonic pole is right. If upper wing is concave downwards, then sound column is short, and if it is inclined upwards, then sound column is too long. If wrong speaker is not replaced as soon as possible, curvature of panel can easily be deformed and problem will be even greater.
Some careful people will switch to different speaker lengths in winter and summer, which is not really necessary. However, it is necessary to ask experienced specialists to make small adjustments to position of speaker, depending on climatic changes.
Don't be complacent to tap and change position of sound pole at will, correct length and position of sound pole in piano, and its top and bottom ends absolutely matching back of piano and inside of panel, and its position relative to bass beam. Whether or not vibration of the piano body is appropriate due to mutual symmetry is a very delicate and painstaking work. Please refer to this article for speaker installation position –> Violin speaker installation position and installation method