Sound vibration

“ Here are some of them.
“Vibration,” he said, elaborating on the outline he had formerly given Peregrine, “is the first law to study. There is no single thing in the universe which does not emit vibrations,—matter, colour, light, and sound. To comprehend the whole riddle of life is but to attune oneself to the reception of these vibrations, and interpret them rightly. Like rushes to like. To make my meaning clearer, sound—the crash of a falling tree for example—emits vibrations to the ether. They travel across it till they reach some instrument attuned to receive them. ”

“ The tuning fork is musical. Here we have rapid, regular motion; vibrations follow each other at perfectly definite intervals, and the air disturbance produced by one vibration is exactly like the disturbance produced by a later vibration. The sound waves which reach the ear are regular in time and kind and strength, and we call the sensation music.
To produce noise a body must vibrate in such a way as to give short, quick shocks to the air; to produce music a body [279] must not only impart short, quick shocks to the air, but must impart these shocks with unerring regularity and strength. ”

“ Each vibration of the sound adds to the pressure upon the glass of its own vibration. Instead of the edges drawing closer by the one-thousandth of an inch, let us say, the sound vibration causes the edges to draw closer by two-thousandths of an inch. And that strain, repeated, not normal, will sometimes shatter the glass. But the sound vibrations must be exactly as numerous as the glass vibrations. Otherwise, the sound vibrations, instead of accelerating the glass vibrations, will impede and stop them. ”

“ All agitation is vibration. All force manifests itself in this way.
The painful brilliancy of the sun is produced by the rapid vibrations of the rays; the twinkle of the distant star, the waves of the ocean when ruffled by the winds; the shimmer of the moon on its crested surface; the brain in thinking; the mouth in talking; the beating of the heart; all, alike, obey the one grand and universal law of vibratory motion.
Qualities of Sound.—Sound is nothing but a succession of vibrations of greater or less magnitude. Pitch is produced by the number of vibrap. 157tions; intensity by their force ”

“ The structural basis of Music is vibration. Sound comes to us in the guise of air-waves, which impinge upon the drum of the ear. The nerve-impulse thus aroused is conveyed to the brain, and there translated into sound. Strictly speaking there is thus no sound until the brain translates the message, while if the machinery of the ear be too dull to answer to the vibration the sound simply does not exist for us. ”

“ It is also through the vibrations conveyed by the air to the little membrane called the drum of the ear that the sensations of sound are received, and of the nature of these vibrations a few words must be said presently. In considering the different qualities of sound, we have so far confined ourselves to sustained musical notes, as, for instance, the vowel sounds in singing. This has been done to show the relations of rapidity of vibration to pitch and for simplicity of illustration of the superposition of vibrations, etc. ”

“ Not only so, but the amplitude of vibration in the one will determine the amplitude of vibration in the other, for the intensity of the induced current is determined by the amplitude of the inducing vibration, and the amplitude of the vibration at the receiving end depends upon the intensity of the attractive impulses. When we sing into a piano, certain of the strings of the instrument are set in vibration sympathetically by the action of the voice with different degrees of amplitude, and a sound, which is an approximation to the vowel uttered, is produced from the piano. ”

“ Sound is produced by vibration; the lowest number of vibrations the ear can distinguish, is sixteen per second, which is known as the low bass notes of an organ. The highest are, approximately, 12,000 per second. These vibrations require power to produce them. ”

“ Hence a woman’s ordinary pitch in the lower sounds of conversation is more than an octave above a man’s; in the higher sounds it is two octaves.
And here it is important to note that by the term vibrations is meant complete ones; and by the term sonorous wave is meant a condensation and its associated rarefaction. By a vibration an excursion to and fro of the vibrating body is to be understood. Every wave generated by such a vibration bends the tympanic membrane once in and once out. These are the definitions of a vibration and of a sonorous wave employed in England and Germany. ”

“ The rate at which the beats succeed each other is equal to the difference between the two rates of vibration.
When a bell or disk sounds, the vibrations on opposite sides of the same nodal line partially neutralize each other; when a tuning-fork sounds, the vibrations of its two prongs in part neutralize each other. By cutting off a portion of the vibrations in these cases the sound may be intensified. ”

“ Sound travels in air at about 1130 feet per second, and if the vibrating body, giving out the sound, oscillates sixteen times in one second, it follows that, spreading over this 1130 feet, there will be sixteen waves, giving a length of about 70 feet to each wave. This is the lowest sound that the human ear can appreciate as a musical note, and is, what may be called, the fourth Octave above one vibration in one second. When the number of vibrations in a second sinks below sixteen, the ear no longer appreciates them as a musical sound, but is able to hear them as separate vibrations or beats. ”

“ Think of a note from a little dog call, or other whistle one and a half inches long, open at both ends, or from a little key having a tube three-quarters of an inch long, closed at one end; you will then have 4,000 vibrations per second.
A wave length of sound is the distance traversed in the period of vibration. I will illustrate what the vibrations of sound are by this condensation traveling along our picture on the screen. Alternate condensations and rarefactions of the air are made continuously by a sounding body. ”

“ Sound is merely vibration, and, once set [187] going, these vibrations will run on and on and on in ripples into the infinite—that is, they will never stop, and sooner or later these vibrations must reach our ears. ”

“ I plainly saw that very low rates of vibration would produce sound, that higher rates would give power in higher and still higher grades of intensity; that higher rates would give chemical action and still more rapid would give beat in a diffused gentle form; increase the rate of vibration still more and we reach the point where red heat gives off the first rays of red light. From this point to the extreme violet light is again only a series of changes in rate of vibration. ”

“ In all ordinary circumstances, sound is the vibration of air. But in swimming we can hear with our ears [pg 181] under water, and fishes hear without any air. So, to be accurate, we should say that sound is vibrations of any kind of matter. And the vibrations travel better in most other kinds of matter than they do in air. Vibrations move rather slowly in air, compared with the speed at which they travel in other substances. It takes sound about 5 seconds to go a mile in air ”

“ The harmonium, accordion, concertina, etc., are reed instruments, the reed for each note being a fine strip of metal vibrating in a slit. The vocal organ of man is at the top of the windpipe, along which a continuous current of air can be forced by the lungs. Certain elastic bands are attached to the head of the windpipe, almost closing the aperture. These vocal chords are thrown into vibration by the current of air from the lungs; and as the rate of their vibration is made to vary by varying their tension, the sound changes in tone. ”

“ In the case of noise the agitation of the air is an irregularly changing motion. In musical sounds, on the other hand, there is a movement of the air in a continuously regular manner, which must be caused by a similar movement in the body which gives the sound. These so-called periodical movements of the sound in the body, rising, falling and repeated at equal intervals, are called vibrations. The length of the interval elapsing between one movement and the next succeeding repetition of the same movement is called the duration of vibration (Schwingungsdauer) , or period of motion. ”

“ Each of the simple sounds which, taken together, constitute the whole sound, causes the vibration of a special group of fibres in the auditory nerve. This fact, often repeated, generates a kind of organic predisposition which is confirmed by heredity. If from any cause one of these groups is set in motion, the other groups will have a tendency to vibrate. ”

“ The sensation of sound is, on its material side, an affection of the auric nerve, under stimulus of regular and periodic air vibrations. The physical pleasure which results from it is entirely dependent on the degree of stimulation, and is therefore conditioned by two variables—the manner of vibration in the air waves, and the particular receptivity of the nerve. ”

“ If you tune two whistles one vibration apart and sound them together, you get a tone that swells once a second; tune them ten vibrations apart and you get ten swellings or beats per second, and the effect is rough and disagreeable. ”

“ Various forms of matter transmit sound vibrations in varying degrees, at different specific speeds, and with different effects upon the vibrations. Any form of matter may serve as a transmitting medium for sound vibrations. Sound itself is an effect of sound vibrations upon the ear. ”

“ We have thus proved, in a simple way, that a musical tone is produced by rapid, regular vibration, as shown by the marking—the air-waves, set up by the vibration, seeming to blend in the ear in a manner similar to that in which the vibrations of the string blend to the eye, which makes the tone seem continuous. ”

“ Hearing, feeling (as regards warmth) and seeing are all produced by vibrations. It is quite in accord with the doctrine of modern science to believe that the morning stars did “sing together,” for light is essentially rhythmic, and to senses adapted to the perception of their harmonies, the sunbeams would make music. The various colors of the spectrum differ solely in the wave-lengths of their vibrations. The red corresponds to low pitch in music and the violet to high pitch. As the vibrations of air striking upon the ear increase in rapidity, the sound [324] rises in the scale. ”

“ Air is the usual vibrating medium. Only certain vibrations are perceptible to the human auditory organ. Those having a recurrence of below thirty or above sixteen thousand per second do not produce the sensation of sound to the average human ear. ”

“ The quickest vibrations which strike the eye, as light, have only about twice the rapidity of the slowest; whereas the quickest vibrations which strike the ear, as a musical sound, have more than two thousand times the rapidity of the slowest. ”

“ Other vocal sounds than sustained vowel notes are found to be due to still more complicated combinations of vibrations of shorter duration, and noises, as distinguished from musical sound, are formed also by the superposition of a greater or less number of systems of vibrations, the rapidities of which are wanting in harmonic relations such as we have pointed out belong to the musical scale. ”

“ Our actual knowledge of the subject is at present limited to mathematics. The velocity of the impulses has been noted and the number of the vibrations has been counted. We know those of sound to be comparatively slow, there being but 4,000 vibrations to the inch in the highest treble note of the piano. Above this on the ascending scale comes a long series of vibrations of which we know little or nothing; and it is not until we reach 36,000 vibrations to the inch that we come again within the range of human sensory consciousness. ”

“ What really passes out from the source is merely a rhythmical motion of the air particles, manifesting themselves as changes in pressure, spreading out in ever-widening spheres through the atmosphere. The order of these compressions is different for every sound. The musical sounds of an orchestra embody a different set of vibrations for each note of each particular instrument. If the fluctuations in pressure of a sound wave are irregular and non-periodic, the sound is called a noise; if they are cyclic, and follow a regular and sufficiently rapid periodic lag, the sound is musical. ”

“ In the inner chamber of the ear physical movements are in some wholly inscrutable manner translated into sensations of sound, and the confused aggregation of waves and ripples in the air, beating against the tympanic membrane there, takes effect in producing impulses which travel up the auditory nerve and expend their energy finally in the creation of sensations of melody and tune, which arouse emotions, revive memories, and stir sometimes the deepest feelings of our minds. ”