Understanding Speaker Parts

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Understanding Speaker Parts

It is very important to understand the parts of a speaker since it helps to demonstrate how speaker specifications compare to each other.  A complete understanding of how a speaker is built internally provides enhanced knowledge that can be visualized to depict what difference count on different type of speakers for the space.

Basic Speaker Parts

The Driver

A loudspeaker is defined as the sound driver or driver.  The driver is the main element of the speaker system since it converts line level voltage from your speaker amplifier into sound by pushing and pulling air molecules in waves that the human ear interests as sound.  A driver can be made from different materials — from the reinforced paper cone shape, a metal dome diaphragm or a carbon fiber element; all within a metal coil.

The Enclosure

Made from wood, plastic and in some cases drywall or concrete, the enclosure is the box or cavity where the driver is mounted. The enclosure can contain one driver or several drivers.
No speaker can exist without an enclosure.  The dimensions of the enclosure determines the volume of air movement, Therefore, the sound force a speaker can create in a given room.  This correlation states that the the size of a speaker enclosure should be related to the size of the room.  A loudspeaker engineered for a bigger room will unfortunately not sound as good in a smaller room. And correlatively, the same holds true for the other way round.

Speaker enclosures come several designs such as ported reflex that have a hole in the front or back to leak more bass.  Fascinating enough, some others are completely sealed — well designed sealed enclosures tend to produce more accurate sound.

Well-made speaker enclosures use structures that have been re-enforced and mostly referred to in speaker specs as a braced enclosure — to reassure that the enclosure vibrate as little as possible to avoid undesirable coloration to sound especially at the resonant frequency of the enclosure which tends to be closer to the upper bass frequencies.

The Diaphragm:

The diaphragm is the device that convert mechanical motion into sound waves.

The Cone:

The cone is a diaphragm which is attached to the voice coil.  The cone is the part that contains a bigger surface and is designed for maximum air movement when the voice coil moves.  The body of the cone can be made from paper, carbon fiber, black polypropolene, aluminum, titanium, phenolic, magnesium, granite, fiberglass, ceramic or kevlar.

The Voice Coil:

Made from copper wire, the voice coil is an electromagnet that provides the motive force to the cone by the reaction of a magnetic field to the current passing through it.  The voice coil is a set of windings wound around an aluminum, nomex, kapton or other material form.  It is made using flat or round wound wire. Nominal impedances are 2, 4, 6, 8, 10, 16 or 32 ohms.

The Dust Cap:

The dust cap is a diaphragm designed to cover the voice coil opening other internal parts of the speaker.  It can be made of paper, aluminum, felt, rubber, screen, or polypropolene.

The Spider:

Made from treated paper coated with adhesive glue, the spider is located internally inside the speaker and its main function is to preserve the voice coil aligned properly and to reassure that the speaker comes back to its normal position between vibrations.  Its like a safety mechanism that ensures all interior parts stay in place. The Spider snuggly fits around the voice coil and is attached to the speaker basket.

The Surround:

The surround is the poly-foam, foam, butyl, accordion or a single cloth or “m” roll cloth ring that holds the cone and the basket together.  It acts as a suspension system that works harmonically with the spider to bring the cone to its normal position between vibrations.

Driver Diaphragm:

The driver diaphragm is attached to the metal basket via an acoustic spider suspension at one end and a flexible surround at the other.

The Basket:

The basket is the structure made from aluminum or plastic that protects all the interior parts and serves as and structural reenforcement so no additional distortions can be created.

The Gasket:

Made from foam, rubber or chip cardboard. The main function of the gasket is to minimize vibration between the driver and the enclosure.

The Magnet:

The magnet is made of a group of metals called the ferromagnetic metals.  These are metals like iron and nikel. These metals have the special property of being capable to be magnetized.  On a speaker the magnet is a big mass located on the back of the speaker.  The magnet serves as an negative or positive inverter for the the voice coil which in returns makes the diaphragms move and make the driver make a sound.

The Assembly:

The diaphragm, spider and surround are firmly attached to a voice coil suspended by a magnetic field created by permanent magnet.  The entire assembly is free to move in accordance with the movement created by the voice coil in response to the electric signal.  This movement moves air in the room to create sound.

Speaker Design

It is very important to understand speaker parts by the way the are designed since speaker design helps to demonstrate how speaker specifications compare to each other.  A complete understanding of how a speaker is built internally provides enhanced knowledge that can be visualized to depict what differences count on different type of speakers. That’s mostly why a great loudspeaker manufacturer spends years and millions of dollars researching and developing a model line that it’s worth to carry the manufacturer’s logo. 

Francisco Hernandez
Francisco Hernandez is the CEO & Founder for Multimedia Tech, an audio, video, automation and IT business specializing in home theater installations, TV installations, home automation and IT systems. Francisco directs business strategies, relations and operations. With nearly 20 years experience, Francisco started as an entrepreneur at the early age of 16 owning and expanding from basic start-ups to small business enterprises.