Speaker driver’s construction and related function
In any sound
system, ultimate quality depends on the speakers. The best recording, encoded
on the most advanced storage device and played by a HIFI speaker and amplifier,
will sound awful if the system is connected with poor speakers.
A system's
speaker is the component that takes the electronic signal stored on things like CDs, DVDs or digtial media such as your smartphone,
tablet, music players, and turns it back into actual sound that we can hear.
A speaker is
essentially the final translation machine -- the reverse of the microphone.
It takes the electrical signal and translates it back into physical vibrations
to create sound waves. When everything is working as it should, the speaker
produces nearly the same vibrations that the microphone originally recorded and
encoded on a tape, CD, LP, etc.
4 inches full range speaker driver unit |
Now, let us
take a look those components or parts of speaker. A typical speaker driver
includ a metal basket, diaphragm (or cone), voice coil, spider, permanent
magnet, ans also include dust cap, terminal,top plate, pole piece.
- The cone, usually made of paper, plastic or metal, is attached on the wide end to the suspension.
- The suspension, or surround, is a rim of flexible material that allows the cone to move, and is attached to the driver's metal frame, called the basket.
- The narrow end of the cone is connected to the voice coil.
- The coil is attached to the basket by the spider, a ring of flexible material. The spider holds the coil in position, but allows it to move freely back and forth.
- The dust cap covers the voice coil opening and sperker internal.
- The terminal with positive and negative is soldered wires where electronic signal come from.
- The top plate and pole piece to fix permanent magnet
Speaker driver's construction, the photo come from network, only for demostration there.Thank you for the original author |
There are key parts for making sound
Diaphragm
A driver produces sound waves by rapidly vibrating a flexible cone,
or diaphragm. Some drivers have a dome instead of
a cone. A dome is just a diaphragm that extends out instead of tapering in.
Voice Coil
When the electrical current flowing through the voice coil
changes direction, the coil's polar orientation reverses.The voice coil is a basic electromagnet. An electromagnet is a coil of wire, usually wrapped around a
piece of magnetic metal, such as iron.
Running electrical current through the wire creates a magnetic field around the
coil, magnetizing the metal it is wrapped around. The field acts just like the
magnetic field around a permanent magnet: It has a polar orientation -- a
"north" end and and a "south" end -- and it is attracted to
iron objects. But unlike a permanent magnet, in an electromagnet you can alter
the orientation of the poles. If you reverse the flow of the current, the north
and south ends of the electromagnet switch.
This is exactly what a stereo signal does -- it constantly reverses
the flow of electricity. If you've ever hooked up a stereo system, then you
know that there are two output wires for each speaker -- typically a black one
and a red one.
Essentially, the amplifier is constantly switching the electrical signal,
fluctuating between a positive charge and a negative charge on the red wire.
Since electrons always flow in the same direction between positively charged
particles and negatively charged particles, the current going through the
speaker moves one way and then reverses and flows the other way. This alternating
current causes the polar orientation of the electromagnet to reverse
itself many times a second.
Magnets
When the
electrical current flowing through the voice coil changes direction, the coil's
polar orientation reverses. This changes the magnetic forces between the voice
coil and the permanent magnet, moving the coil and attached diaphragm or cone
back and forth.
So how does
the fluctuation make the speaker coil move back and forth? The electromagnet is
positioned in a constant magnetic field created by a permanent magnet.
These two magnets -- the electromagnet and the permanent magnet -- interact
with each other as any two magnets do. The positive end of the electromagnet is
attracted to the negative pole of the permanent magnetic field, and the
negative pole of the electromagnet is repelled by the permanent magnet's
negative pole. When the electromagnet's polar orientation switches, so does the
direction of repulsion and attraction. In this way, the alternating current
constantly reverses the magnetic forces between the voice coil and the
permanent magnet. This pushes the coil back and forth rapidly, like a piston.
When the coil
moves, it pushes and pulls on the speaker cone. This vibrates the air in front
of the speaker, creating sound waves. The electrical audio signal can also be
interpreted as a wave.
The frequency and amplitude of this wave, which represents the original sound
wave, dictates the rate and distance that the voice coil moves. This, in turn,
determines the frequency and amplitude of the sound waves produced by the
diaphragm.
Different
driver sizes are better suited for certain frequency ranges. For this reason,
loudspeaker units typically divide a wide frequency range among multiple drivers.
When the
electrical current flowing through the voice coil changes direction, the coil's
polar orientation reverses. This changes the magnetic forces between the voice
coil and the permanent magnet, moving the coil and attached diaphragm or cone
back and forth.
So how does
the fluctuation make the speaker coil move back and forth? The electromagnet is
positioned in a constant magnetic field created by a permanent magnet.
These two magnets -- the electromagnet and the permanent magnet -- interact
with each other as any two magnets do. The positive end of the electromagnet is
attracted to the negative pole of the permanent magnetic field, and the
negative pole of the electromagnet is repelled by the permanent magnet's
negative pole. When the electromagnet's polar orientation switches, so does the
direction of repulsion and attraction. In this way, the alternating current
constantly reverses the magnetic forces between the voice coil and the
permanent magnet. This pushes the coil back and forth rapidly, like a piston.
When the coil
moves, it pushes and pulls on the speaker cone. This vibrates the air in front
of the speaker, creating sound waves. The electrical audio signal can also be
interpreted as a wave.
The frequency and amplitude of this wave, which represents the original sound
wave, dictates the rate and distance that the voice coil moves. This, in turn,
determines the frequency and amplitude of the sound waves produced by the
diaphragm.
Different
driver sizes are better suited for certain frequency ranges. For this reason,
loudspeaker units typically divide a wide frequency range among multiple drivers.
There are more HIFI speaker driver units that cover most of the kinds on the market. More details, please find
2.25 inches full range speaker driver unit |
4 inches full range speaker driver unit |
5 inches full range speaker driver unit |