WHAT IS LOUDSPEAKER?
A loudspeaker or speaker is a device that converts electrical energy waves into mechanical energy waves or audible sounds. Sound is produced by the vibration of an object. This vibration sets up a series of ripples or waves much like what is seen when a stone is thrown into a pond. Speakers reproduce sound waves (or audio) at various frequencies. The frequency is the rate at which the particles in the air vibrate. Sound that the human ear can hear is from about 20 hertz (Hz) to 20,000 Hz or 20 kilohertz (kHz). Speakers are used in all types of communications and entertainment equipment such as radio and television receivers, tape recorders, telephone answering machines, baby monitors, and stereo home entertainment systems Paper was used in the construction of speaker cones because it is cheap and readily available.
MANUFACTURING PROCESS
Raw Materials
The dynamic speaker has not changed in decades. The frame is made from stamped iron or aluminum. The permanent magnet is a ceramic ferrite material consisting of iron oxide, strontium, and a ceramic binder. The cone, surround, and spider are made of treated paper coated with an adhesive glue. The voice coil consists of a plastic bobbin with fine gauge insulated copper wire wound around it. There are four major types of speakers: full-range, tweeter, midrange, and woofer.
Manufacturing process
The permanent magnet is constructed by mixing iron oxide with strontium and then milling the compound into a very fine power. The power is mixed with a ceramic binder and then closed in a metal die. The die is then placed in furnace and sintered to bond the mixture together.
The frame is constructed from an aluminum or steel sheet. The sheet arrives at the plant preformed. It is then placed on a conveyor belt and transported to a cutting machine that used a hydraulic press to cut holes in the sheet to allow free air movement from the cone. The sheet is then formed by a hydraulic press that forces the sheet into a die of the desired shape.
The cone, surround, and spider are individually formed out of composite paper and then glued together as an assembly.
The voice coil is built by winding many turns of very fine insulated copper wire on a plastic bobbin. The bobbin and voice coil assembly is glued to the dust cap of the cone assembly.
The frame, soft iron core, and permanent magnet are bolted together as an assembly.
The cone assembly is then attached to the frame assembly by first manually gluing the spider to the base of the frame and then gluing the surround to the top of the frame.
Quality Control
Inspectors monitor all steps of the manufacturing process. The permanent magnet is checked for chips or cracks. The paper cones are inspected for flaws or holes in the material, and proper gluing of the cone assembly. The entire assembly is inspected for overall quality and adherence to specifications. The final speaker assembly is connected to an audio generator that tests the frequency response and power capabilities of the speaker to insure that in produces sound within the required specifications.
Byproducts/Waste
Scrap metal from the frame and scrap paper from the cone are sent to recycling plants for reclamation. Exotic materials such as strontium must be disposed of according to government regulations.
The Future
The industry is constantly experimenting with raw materials to improve speaker sound quality, frequency response, and power output. New technologies are being developed in the form of a direct-drive speaker that uses no cone.
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DISCLAIMER
The information is provided by Tecquisition for general informational and educational purposes only and is not a substitute for professional legal advice. If you have any feedback, comments, requests for technical support or other inquiries, please mail us by tecqusition@gmail.com.
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