Examples
On-line sound examples comparing pure and complex tones and complexes with missing fundamentals can be found here.
Timpani (kettle drums) produce inharmonic overtones, but are tuned to produce near-harmonic overtones to an implied missing fundamental. Hit in the usual way (half to three-quarters the distance from the center to the rim), the fundamental note of a timpano is very weak in relation to its second through fifth "harmonic" overtones. A timpano might be tuned to produce sound most strongly at 200, 302, 398, and 488 Hz, for instance, implying a missing fundamental at 100 Hz (though the actual dampened fundamental is 170 Hz).
A violin's lowest air and body resonances generally fall between 250 Hz and 300 Hz. The fundamental frequency of the open G3 string is below 200 Hz in modern tunings as well as most historical tunings, so the lowest notes of a violin have an attenuated fundamental, although listeners seldom notice this.
Most common telephones cannot reproduce sounds lower than 300 Hz, but a male voice has a fundamental frequency approximately 150 Hz. Because of the missing fundamental effect, male voices still sound male over the telephone.
The missing fundamental phenomenon is used electronically by some pro audio manufacturers to allow sound systems to seem to produce notes that are lower in pitch than they are capable of reproducing. In a hardware effects unit or a software plugin, a crossover filter is set at a low frequency above which the sound system is capable of safely reproducing tones. Musical signal content above the high-pass part of the crossover filter is sent to the main output which is amplified by the sound system. Low frequency content below the low-pass part of the crossover filter is sent to a circuit where harmonics are synthesized above the low notes. The newly created harmonics are mixed back into the main output to create a perception of the filtered-out low notes. Using a device with this synthetic process can reduce complaints from low frequency noise carrying through walls and it can be employed to reduce low frequency content in loud music that might otherwise vibrate and damage breakable valuables.
A pipe organ sometimes makes use of this phenomenon as a resultant tone.
Read more about this topic: Missing Fundamental
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