Scientists and musicologists have long sought the secrets behind the superb sound produced by Stradivarius and del Gesu instruments. Many theories have nevertheless proved unsuccessful as the modern instruments were duplicated to the smallest details of the famous ones. However, in an article recently published at PloS ONE, Berend C. Stoel and Terry M. Borman have noticed one difference between the real one and the copy - the density of the wood. The men put the two instruments into a medical scanner designed to capture images of human lung density and found a small difference in the density of the woods. The Stradivarius violins had a higher wood density, which may possibly explain the higher quality of sound produced. Read the entire article here at PloS ONE.