This phenomenon has been known for several centuries. The Italian violinist Giuseppe Tartini (1692-1770) spoke of the terzo souno or third sound generated from 2 sounds. The third sound can help with regards to tuning the two original notes. A major third is perfectly tuned if the generated note is two octaves lower than the bass note. Any change in the tuning of the top note will be reflected in the frequency of the third sound:
Organ constructors use of this phenomenon to produce low-pitched sounds with smaller pipes. Two pipes tuned to a perfect fifth will generate a sound one octave lower than the lowest sounding pipe.
The fact that our auditory system can complete missing harmonics, makes possible to listen to music in sound systems that are not capable of producing low frequency sounds.
Finally, let's experiment with the Tartini effect. We suggest using headphones. Be careful that the volume is not too high!
The G4 is a perfect fifth above the C4 and is tuned using the size of the fifth of the harmonic series: 260 x 1.5 = 390. The perfect fifth of the equal temperament system - commonly used today - is 2 cents smaller than the fifth of the harmonic series. Note the effect of this small change in tuning.
If you would like to know why the equal temperament has smaller fifths, follow this link to read about tuning systems...
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© 2017 José Rodríguez Alvira. Published by teoria.com