More Than Meets the Ear: The Invention of the Loudspeaker
- Tuesday, November 08, 2011
Most of what we hear is in between these two limits. As a result, loudspeakers are designed to project frequencies across this range. Low frequencies require very large loudspeakers, and high frequencies require very small loudspeakers. Here are some of the more common loudspeaker designs:
•Full-Range Driversattempt to provide the broadest range of sound with a single speaker. These speakers range from about 3” in diameter to about 8” in diameter. Some have modifications to help reach into the higher frequencies, but they remain limited and do not do very well when it comes to bass notes.
•Subwoofersare specialized speakers meant to reproduce the lowest sounds. The construction of subwoofers is simple, but very important. Because they project only the lowest sounds, they are built in rigid cases. The lowest notes will vibrate pieces loose if the subwoofers are not well designed and assembled.
•Woofers,as one might expect, are used for low pitches, but they handle pitches higher than do subwoofers. The frequency response of woofers makes them able to handle some very low notes, as well as some mid-range notes.
•Mid-Range Driversreproduce middle frequencies.
•Tweetersare high-frequency speakers used to reproduce the highest notes in a sound system.
Where Are Loudspeakers Used?
Loudspeakers are used in many other places besides sound systems.
Telephones, cell phones, and similar devices all have loudspeakers inside. Computer systems often have loudspeakers connected either internally or externally. Kitchen appliances, like microwaves and ovens, have loudspeakers that tell you when cooking is completed or a temperature has been reached. Hearing aids have tiny loudspeakers inside. Airline, train, subway, and bus stations have loudspeakers throughout the facility so people can hear announcements.
Try this some time: for one day, pay attention to the sounds you hear around your home, and make a list of everything that has a loudspeaker in it. You will be surprised by how many you find, and maybe even more surprised by where you might find them. One hidden location for a loudspeaker, which you hopefully never hear, is inside of a smoke detector!
Want to Learn More?
If you are interested in learning more about sound, check out Music, Physics, and Engineering by Harry F. Olson. The book is nearly 50 years old, and while technology has changed, the underlying physics have not. Our oldest son modified a box for a bass speaker using what he learned from this book. The modification was simple and made a big difference in the quality of the sound from his music system.
Ray and Gale Lawsonhave been homeschooling their three children since 1995. Ray holds a BS in Electrical Engineering from the Virginia Military Institute and is also a student, pursuing a Masters in Nuclear Engineering at the University of South Carolina. He works for Savannah River Nuclear Solutions, LLC. Gale holds a BS in Mechanical Engineering from the University of South Carolina and is full-time mom and teacher. They are members of Breezy Hill Baptist Church in Graniteville, SC. Questions, comments, and suggestions are always welcomed and can be e-mailed to them at firstname.lastname@example.org (Ray) or email@example.com (Gale).
This article was originally published in the Jan/Feb 2011 issue of HomeSchoolEnrichment Magazine. To learn more, and to request a FREE sample copy, visit www.HomeSchoolEnrichment.com
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