Amount of a waveform's deviation from center. When used to describe sound, amplitude means volume. [Friend, David, Learning Music with Synthesizers]
The difference between 0 and maximum or minimum changes of polarity within a wave or cycle.
The magnitude of periodic dynamic motion (vibration). Amplitude is measured in terms of peak-to-peak, zero-to-peak, rms, or average. [Field of Rotating Machinery Measurment, Monitoring and Analysis, Bentley Nevada Corporation]
Amplitude refers to the strength, or loudness, of a sound, or of the strength of an electrical signal representing sound. If the sound or signal is represented as a wave pattern on an oscilloscope or graph, the amplitude corresponds to the height of the wave (i.e., the magnitude of the swing in each cycle). [Fantel, Hans, The True Sound of Music - A Practical Guide to Sound Equipment for the Home]
Keely
"Given that force can be exerted by an act of will, do we understand the mechanism by which this is done? And if there is a gap in our knowledge between the conscious idea of a motion and the liberation of muscular energy needed to accomplish it, how do we know that a body may not be moved without ordinary material contact by an act of will? Keely contends that all metallic substances after having been subjected to a certain order of vibration may be so moved. "Scientists are verging rapidly toward the idea that immense volumes of energy exist in all conditions of corpuscular space. I accept Prof. Stoney's idea that an apsidal motion might be caused by an interaction between high and low tenuous matter, but such conditions, even of the highest accelerated motion are too far down below the etheric realm to influence it sympathetically, even in the most remote way. The conception of the molecule disturbing the ether, by electrical discharge from its parts is not correct... the highest conditions associated with electricity come under the fourth descending order of sympathetic conditions. The conjecture as regards the motion being a series of harmonic elliptic ones, accompanied by a slow apsidal one, I believe to be correct... The combination of these motions would necessarily produce two circular motions of different amplitudes whose differing periods might correspond to two lines of the spectrum as conjectured, and lead the experimenter, perhaps, into a position corresponding to an ocular illusion. Every line of the spectrum, I think, consists not of two close lines, but of compound triple lines; though not until an instrument has been constructed, which is as perfect in its parts as is the sympathetic field that environs matter, can any truthful conclusion be arrived at from demonstration." [Keely] [FORCE - Snell]
Russell
"The question has long been asked by research scientists why it is that the inert gases will not mix, or unite with "any of the other elements." The first answer is that the inert gases are not electrically divided and conditioned elements, as all of the others in the nine octaves are. The inert gases begin in the first octave as invisible white fluorescent light of zero motion. They end at the 9th cathode in the 9th octave, as visible white fluorescent light, which has reached a speed of nearly 186,400 miles per second. Fluorescent light is that light which begins in the undivided electric spectrum. It is the beginning and end of motion. All motion is either red or blue, according to its sex. The end of motion at the amplitude of the 9th octave means that the divided spectrum has been united as one colorless, sexless light which has been under such high compression that it has reached its limit of conditioning by motion and must be transformed from the white light of visible motion to the invisible white Light of Magnetic stillness. The fluorescent light is that ending of electric power to divide motion into pairs, and to condition the pairs with the opposing sex tensions of electrically divided spectrum opposites. The inert gases are not pairs. They are not divided. Division takes place by light projected from them, but that projected light of spectrum pairs is the basis of the electrochemical elements, which have great volume and density in comparison." [Atomic Suicide, page 261-262]
Ramsay
If the effects of notes and chords had depended entirely on their mathematical ratios, then the effect of the subdominant, tonic, and dominant would have been alike; for these three chords have exactly the same ratios. It is the law of position which gives the tonic chord its importance, and not any special ratios embodied in its structure. The ratio of 2 to 1 has a pure, unmixed, invariable character, always realized in the interval of the octave. The notes produced from 1 by the first, second, and third powers of 3 have different degrees of centrifugal force. The character of the notes produced by the first power of 5 depends on the character of the notes from which they are derived, namely, 1, 3, and 9. The final character of the notes and chords derived by the same ratios is determined by the amount of force which they have acquired from the way in which they have been derived, and from their position in the system; and no matter where these notes may afterwards be [Scientific Basis and Build of Music, page 37]
See Also
4plusplus
Aggregation
amplitude element
Amplitude Modulation
Amplitude of Force
amplitude of the wave
amplitude wave position
Concentration
first comparison and combination of quantities
Intensity
laws of quantities and motions
multiplied amplitude
order of quantities
quadrature amplitude modulation
quantities and motions
thought wave amplitude
wave amplitude