**Figure 8.6 - Difference Tones**

**Ramsay**

A *grave harmonic* is a secondary note which spontaneously arises when two different notes are sounded together. It is a note whose mathematical number is the **difference of the two** which awaken it; *e.g.*, F2 and C3, the interval of the fifth, awakens a *grave harmonic* whose number is 1, which is the difference of 2 and 3; and this 1 strengthens F2, for it is its lower octave. But the interval of F2 and F4, or any other octave, does not awaken a *grave harmonic*, since there is no difference-number between the two. - Editor. [Scientific Basis and Build of Music, page 36]

See Also

**Difference Tone**
**Figure 8.5 - Summation Tones**
**grave harmonic**
**Harmonic**
**Interval**
**Law of Harmonic Pitch**
**Law of Harmonic Vibrations**
**LAW OF SUPERPOSITION**
**Overtone**
**Overtone Series**
**Overtones Developed Musically**
**Power of Beat Harmonics**
**Resultant Tone**
**Undertone**
**1.23 - Power of Harmonics through Summation Tones**
**9.9 - Sympathy or Harmony Between Harmonics or Overtones**