Page:Popular Science Monthly Volume 45.djvu/87
PECULIAR SOUND EFFECTS.
dustry of the Atlantic coast to show that it is an important source of national wealth, and I believe it will reasonably be deduced, from what I have written, that nothing but restrictive laws in several States prevents it from becoming of vastly greater importance.
By A. A. KNUDSON.
IN this article we propose to consider some of the peculiar features and effects of sound as we meet them in our everyday life, giving special reference to that very oft perplexing phenomenon the location of various sounds. In order that these remarks shall not extend beyond reasonable limits in our treatment of this broad subject, we shall confine them to sound effects as they originate indoors, and not so much to the origin and transmission of sounds in the atmosphere. The inability to determine at once whence a sound comes, or, as is often the case, locating it in the wrong place, occasions frequent trouble and annoyance, as we shall show by incidents in our own experience, extending over a number of years.
In order that those not familiar with the subject may obtain a fair idea of the peculiar effects of sound, as we shall herein illustrate, let us look briefly at some of its principles. In the science of acoustics, sound is simply vibrations or pulsations originating from an unlimited variety of causes, varying in amplitude, pitch, etc., passing through the intervening air, and acting upon the organs of the ear. The phonograph gives us an excellent illustration of the composition of these vibrations, for by examining with a magnifying glass the cylinder upon which the human voice has been placed either in spoken words or vocal music, we find all the vibrations which go to make up the different characteristics of sound faithfully recorded in the indentations upon the cylinder, I say faithfully recorded, because their correct reproduction is a proof of this — the result being the same also if other than vocal sounds are recorded upon the cylinder, such as music from instruments either single or combined.
If we follow the lines made by the vibrations closely, we shall see in the indentations deep and coarse punctures which represent the loud base notes of the male singer or speaker, while the fine, light, and more frequent indent represent the high notes of either a male or a female voice, and the same effect is produced by the vibrations of sounds made by musical instruments. The phonograph, therefore, enables us to capture, as it were, all manner of sounds, and to give them optical expression, while