Radio broadcast .. (1922-30)

How Loud Shall the Loud Speaker Speak? By R. H. MARRIOTT Radio Aide, United States Navy, Bremerton, Washington N THE dining, dinning or dancing room of a certain popular United States city hotel, several young fellows with slick hair and urban manner supply power intermittently to saxophones, drums, horns, pieces of wood, pieces of metal, and a piano. The room is full to overflowing with the sounds they produce. Twenty miles away, at the end of a trail and between hills, in a little clearing in the big timber, is a log cabin. There, the finest phonograph records are played with a very soft fibre needle. There are woods sounds and a babbling brook. There is no din. And there are many who walk miles to enjoy that place. I live between those two places and hear radio broadcasting, and hear criticism of what broadcasters broadcast, and criticism of what loud speakers speak. Some criticisms deal with the subject of loudness. For example the Watts family has the Listener family in to hear their radio, and the next day Mrs. Listener remarks to a neighbor that the Watts' s radio loud speaker is too loud, and Mr. Listener tells his fellow men that the Watts's radio is mighty noisy. On the other hand some listeners are dissatisfied with other radios because the sounds are too faint. "What is normal loudness?" is often asked. A good answer is: "Conversational loudness is normal loudness." A good rule is to adjust the radio equipment so that the broadcast announcer talks as loudly through the speaker as he should talk if he himself were in the room. In the quiet home, very little power is required to bring the sound to the ears at conversational loudness. In a boiler shop conversational loudness needs to be as loud as in a quiet place, and must also be as loud as the boiler shop noises. In the boiler shop, the ears are strained and the voice is strained. The sound is painful and the producing of the sound waves is painful. Loud speakers should not be operated in a way that pains the listeners and strains the radio equipment. If the loud speakers are operated in a noisy place, they must be operated louder than the noises. In trying to make the broadcast louder than the local noises the radio and sound equipment may be strained so the equipment adds squeaking or sputtering sounds. Usually the next step is to make the speaker speak still louder so the broadcast that the speaker gives out, added to the noise it gives out, are together very much louder than the local noises, and then the broadcast is heard. That hearing is sometimes a painful process. The tendency to overcome local noises by making a loud speaker speak louder is wrong because instead of securing pleasing sounds, that method, if pursued far enough, will certainly produce painful loudness. If the same amount of effort, thought, and money are applied to eliminating the local noises, better results should be obtained. Closing a door will sometimes shut out more noise than one amplifier could overcome. And if the broadcasting station is close enough, a crystal detector can furnish power enough to give pleasing results in a soft walled room. Not only is painful loudness sometimes the result of attempting to drown out interfering loud noises, but painful loudness and straining of receiving equipment is sometimes the result of attempting to overcome reflection of sounds. For example: If part of the sound from the speaker comes direct to the ear while another part of that same sound goes direct to a hard surface and is there reflected to the ear, that reflected sound is usually an interference. The reflected sound has traveled farther and therefore does not enter the ear with the same sound it started with. It more or less deforms the direct sound that is entering the ear when it gets there. If all of the sound given by the speaker is small, then the undeformed difference between the strength of the direct sounds and reflected sounds may be too small to be