Carbon microphone technology was integral to the processes of first telephones invented (1), making it very important to the way communication happens today. The telephone sparked a new revolution in how people were able to communicate with one another. People from different regions could be in contact with one another in only a few short seconds, this deeply strengthened relationships as telephones, today and back when they were invented, allow for humans to business with one another, share ideas, and noteworthy events and news between one another regardless of physical distances. This is something that was very difficult to do before the rise of the telephone.
The carbon microphone's technology is unique because it relies on two plates with carbon dust in-between them. On one side of the carbon dust is a metal plate and on the other side is a diaphragm (2); a diaphragm is a thin piece of material that vibrates when hit with sound waves (3). As sound waves ram into the diaphragm, they compress the carbon dust, increasing the pressure on the dust. The changing pressure on the carbon changes the amount of current that flows which produces varying pressure of the sound waves (4). The electrical current from the battery is able to run through the compressed carbon. Within a telephone system, the current then changes the sound into an electrical signal as it passes through the system (5). |
The image shows inventor Emile Berliner seated next to one of the first carbon microphones, one he and Thomas Edison originally invented in the late 1870's, in 1929 (6). Berliner received the Franklin Gold Medal because his contribution in the world of microphones was so important and made such an impact because of its connection with the telephone. Over in England, within a few years of Berliner and Edison, David Edward Hughes was credited with inventing the first model of the carbon microphone that could stand alone.
Diagram of the Carbon Microphone showing the carbon granules. (7)
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A diagram of the inner workings of the electret microphone provided by Northwestern University (14).
This image shows how small an electret actually is. Currently, most electret production is in China and electrets placed in laptops and cell phones that are exported and used all over the world. (15) University of Michigan School of Music professor Jason Corey states that in the future we should see even smaller microphones than the electret because "microphones are decreasing in size, just like everything else, but I expect that microphones will be smaller and be less obtrusive" in the future (16). So, while telephones slim down even more, we can plan to see microphones that get even smaller than the electret. This could possibly make communication even easier between people.
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As telephones became smaller and slimmer, the microphones within them did too as the first stable electret microphone is introduced in the 1970's (8). This microphone is a type of condenser microphone but relies on an electret to charge (9). An 'electret' is a stable insulating material with a permanently-embedded static charge which means that electret microphones require only a small amount of power from a battery to charge and then can function for hours without being attached to the battery (10).
The effects of this microphone extend the effects that the carbon microphone had on communication. More specifically, the production and effects of this microphone fall under what is known as the "sixth wave of innovation" (12) that started in the 1970's and continues through today. The sixth wave of innovation has had a huge impact as one of the biggest results of it was the "draw[ing] all parts of the world more tightly together than ever before" (13). The electret microphone has played a huge role within the tight integration of the sixth wave because of its ability to function sans wires. Working without constantly needing to be charged from am outside source allows the electret microphone to further improve communication methods as for example, a businessman from South Africa can Skype with a product retailer in Australia in a matter of seconds to discuss a product from their cars, the sidewalk, or even a restaurant after a short charge of the phone or computer. The societal effects page has more explanation on the increasing global connections made possible by the microphone and phone technology. |
1. Douglas Kahn, Earth Sound Earth Signal (University of California Press, 2013; ProQuest), Chapter “Microphonic Imagination,” http://site.ebrary.com.proxy.lib.umich.edu/lib/umich/detail.action?docID=10743908.
2. F.S. Goucher, “The Carbon Microphone: An Account of Some Researches Bearing on Its Action,” Bell System Technical Journal 13, no. 2 (April 1934): 164, http://onlinelibrary.wiley.com/doi/10.1002/j.1538-7305.1934.tb00658.x/abstract.
3. Tom Lubin, Getting Great Sounds, ed. Mark Garvey (Boston: Course Technology Cengage Learning, 2010), 3.
4. F.S. Goucher, “The Carbon Microphone: An Account of Some Researches Bearing on Its Action,” Bell System Technical Journal 13, no. 2 (April 1934): 164, http://onlinelibrary.wiley.com/doi/10.1002/j.1538-7305.1934.tb00658.x/abstract.
5. Eliot Van Buskirk, “The Microphone Sounds Much Better,” Wired, March 4, 2010, http://www.wired.com/2010/03/0304berliner-invents-microphone/.
6. Harris & Ewing, Inventor of microphone to receive Franklin Gold Medal. On May 15th, Emile Berliner, Washington Scientist, will appear for the third time..., 1929, Library of Congress Online Photo Catalog, Washington D.C., http://www.loc.gov/pictures/item/hec2013005424/.
7. Carbon Granule Microphone,School Physics. http://www.schoolphysics.co.uk/age11-14/Electricity%20and%20magnetism/Electromagnetism/text/Carbon_microphone/index.html.
8. Bob Heil and Allen Pitts, “The Microphone: A Short Illustrated History,” QST 90, no. 6 (June 2006): 50, http://search.proquest.com/docview/228573954?accountid=14667.
9. “Electret Condenser Microphones,” BeStar, accessed March 27, 2015, http://www.bestartech.com/base_mount.html.
10. “Choosing a Type: Microphone Types and Uses,” Sound on Sound, June 1995, http://www.soundonsound.com/sos/1995_articles/jun95/microphones.html.
11. “Electret Condenser Microphones,” BeStar, accessed March 27, 2015, http://www.bestartech.com/base_mount.html.
12. David Christian, Maps of Time: An Introduction to Big History (Berkeley: University of California Press, 2011), Chapter 14.
13. David Christian, Maps of Time: An Introduction to Big History (Berkeley: University of California Press, 2011), Chapter 14.
14. Electret Microphone, Northwestern University. http://hades.mech.northwestern.edu/images/8/80/ElectretMicrophone.gif.
15. Electret Microphone, Adafruit. http://www.adafruit.com/products/1064.
16. Jason Corey, interview by Shelby Timmer, April 4, 2015.
2. F.S. Goucher, “The Carbon Microphone: An Account of Some Researches Bearing on Its Action,” Bell System Technical Journal 13, no. 2 (April 1934): 164, http://onlinelibrary.wiley.com/doi/10.1002/j.1538-7305.1934.tb00658.x/abstract.
3. Tom Lubin, Getting Great Sounds, ed. Mark Garvey (Boston: Course Technology Cengage Learning, 2010), 3.
4. F.S. Goucher, “The Carbon Microphone: An Account of Some Researches Bearing on Its Action,” Bell System Technical Journal 13, no. 2 (April 1934): 164, http://onlinelibrary.wiley.com/doi/10.1002/j.1538-7305.1934.tb00658.x/abstract.
5. Eliot Van Buskirk, “The Microphone Sounds Much Better,” Wired, March 4, 2010, http://www.wired.com/2010/03/0304berliner-invents-microphone/.
6. Harris & Ewing, Inventor of microphone to receive Franklin Gold Medal. On May 15th, Emile Berliner, Washington Scientist, will appear for the third time..., 1929, Library of Congress Online Photo Catalog, Washington D.C., http://www.loc.gov/pictures/item/hec2013005424/.
7. Carbon Granule Microphone,School Physics. http://www.schoolphysics.co.uk/age11-14/Electricity%20and%20magnetism/Electromagnetism/text/Carbon_microphone/index.html.
8. Bob Heil and Allen Pitts, “The Microphone: A Short Illustrated History,” QST 90, no. 6 (June 2006): 50, http://search.proquest.com/docview/228573954?accountid=14667.
9. “Electret Condenser Microphones,” BeStar, accessed March 27, 2015, http://www.bestartech.com/base_mount.html.
10. “Choosing a Type: Microphone Types and Uses,” Sound on Sound, June 1995, http://www.soundonsound.com/sos/1995_articles/jun95/microphones.html.
11. “Electret Condenser Microphones,” BeStar, accessed March 27, 2015, http://www.bestartech.com/base_mount.html.
12. David Christian, Maps of Time: An Introduction to Big History (Berkeley: University of California Press, 2011), Chapter 14.
13. David Christian, Maps of Time: An Introduction to Big History (Berkeley: University of California Press, 2011), Chapter 14.
14. Electret Microphone, Northwestern University. http://hades.mech.northwestern.edu/images/8/80/ElectretMicrophone.gif.
15. Electret Microphone, Adafruit. http://www.adafruit.com/products/1064.
16. Jason Corey, interview by Shelby Timmer, April 4, 2015.