Most musicians agree that the best violins were first made in Cremona, Italy, about 200 years ago. These violins sound better than any other violin. They even sound better than the violins made today. Violin makers and scientists try to make instruments like the Italian violins. But they aren't the same. Musicians still prefer the old ones.
Some people think it is the age of the violins. But not all the old violins sound wonderful. Only the old violins from Cremona are special. So age cannot be the correct answer.
Other people think the secret to those violins is wood. The wood must be from certain kinds of trees. But the kind of wood may not be so important. It may be more important to cut the wood in a special way. Wood for a violin must be cut very carefully. It has to be the right size and shape. The smallest difference will change the sound of the violin. Musicians sometimes think that it is the secret of the Italians. Possibly they understood more than us about how to cut the wood.
Size and shape may not be the answer either. Scientists can make new ones which are exactly the same size and shape. But the new violins still do not sound as good as the old ones. Some scientists think the secret may be the varnish (清漆). Varnish is what covers the wood of the violin. It makes the wood look shiny. It also helps the sound of the instrument. But no one knows what the Italian violin makers used in their varnish.