A speaker is a device that is used to convert an electrical audio signal or sound waves into a corresponding sound. It can also be referred to as an electroacoustic transducer that is, it consists of an enclosure and electrical connections including a crossover network to produce sounds. The sound produced from speakers differs based on the amplitude and frequency of the sound.
Amplitude refers to the loudness of the sound while frequency determines whether the should be high or low pitched. A good speaker should be able to generate electrical signals or sound waves accurately to produce various sounds over a broad range of frequencies. Speakers that have volume control and demand a power source are usually amplified and often used.
TYPE OF SPEAKERS
There are basically four types of speakers and they include. Tweeter, Midrange, Full-range, and lastly the Woofer. The full range only has the ability to reproduce most of the audio sound range while the other types are designed to overcome the limitations of the aforementioned speaker.
COMPONENTS OF A SPEAKER
As it is known that the most common type of speaker is the dynamic speaker, and it is usually found in different home sound systems, like radios, Televisions, and professional speaker monitors. The following are the most common components of a dynamic speaker:
- The Top plate
- The yoke
- The Basket or a Frame
- The Voice coil
- The Cone
- The Spider
- The Magnet
- The Surround
THE TOP PLATE
The top plate together with the yoke and magnet typically completes the magnetic circuit of a speaker. It should not be too thick or thin in order for the quick trigger of the sound waves and to avoid the loss of sensitivity and dynamics. The inside and outside diameters are so critical that is, it is typically made of iron and provides a means to channel the magnetic field into the space around the voice coil.
The yoke is an expensive and heavy lump of metal at the back of a speaker, it is designed to stabilize the magnet assembly to produce sounds and manages its efficiency. It also has a great effect on the distortion mechanisms and voice coil temperature which in turn affect the thermal compression and power handling.
In the making of a dynamic speaker, the basket or frame which basically made from stamped iron or metal and gives a sturdy framework to support the rest of the speaker components. The basket is constructed using AI or steel sheet, by using a cutting machine to cut holes in the sheet to allow free flow of air movement from the cone. The sheet is now used to form the desired shape.
The magnet is permanently connected to the backside of the basket and also is secured in place by a metal top plate and a backplate. The basket is often used to supports the cone surround and the permanent magnet assembly
THE VOICE COIL
The voice coil is a thin copper wire that is usually wound around a plastic bobbin. This bobbin is now placed on the top of a soft iron core and sits inside the opening of the basket. Voice coils also move the diaphragm through the magnetic field created by the electric current wire. The voice coil is built by winding several turns of fine insulated copper wire on a plastic bobbin and the wires with high frequency from the voice coil are then connected to an audio amplifier used to produce sounds.
This is the biggest part of the speaker which is covered by a dust cap, it determines the frequency response of the electric current and the overall sound of the speaker. The cone surround is individually formed out of composite paper and then glued together as an assembly. The cone assembly is attached to the frame assembly, and the spider is manually glued to the top of the frame and then attached to the basket assembly. The shape of the profile of the cone is extremely important, for instance, a driver designed for a 2-way system will surely have a different cone profile to a subwoofer.
The spider is a small flexible piece of plastic that is attached to the speaker basket. It also serves as a type of suspension that usually keeps tension on the voice coils to allow it to move, and act similarly to the struts on car audio which reduces unnecessary vibration. The spider can be soft or hard and has different size voice coil openings, it can be flat or cup-shaped.
Significantly, speakers rely on electromagnetism which deals with electric signals to act effectively as transducers. Magnet is rare earth neodymium that serves as a driving force of a speaker, it is available in a wide variety of specifications and sizes. The center of the large magnet is suspended below the voice coil that is attached to the terminals on the basket.
The surround also called the front suspension is a piece of the lining that is used to connect the basket with the diaphragm. Together with the suspension, it is attached to the cone and controls the cone excursion, and also determines how energy travels back and forth through the cone. When this surround is not working well, it can lead to mechanical failure which is the back and forth movement and general audio distortion.
RAW MATERIALS USED IN THE PRODUCTION OF SPEAKER CONE
The cone surround is a very important part of any loudspeaker or stereo systems to produce sound, it can be made from different raw materials such as paper, plastic, aluminum, and fiber. Each of these materials makes a difference in speaker construction and variably affects the sound quality of the speaker.
Paper is the most commonly used material for speaker cones, It is produced by combining wood, fibers, waxes, and resins together. All these materials are compressed to increase cone flexibility which in return makes the speaker be sensitive. Paper cones are usually used for higher frequencies, like that of tweeter’s frequency.
Plastic is also a popular choice of material used for speaker cones, it gives room for low production cost and inherent consistency of build. It is relatively cheap and offers improved sound-dampening properties. However, the sound dampening properties can mix or disrupt the sound which can limit the frequency range of the speaker.
Cones made of aluminum are always durable and able to reduce wear. Due to the non-flexibility nature of the aluminum, the vibration starts and stops suddenly. It can produce audible peaking and sort of a punchy sound bass response, even though they tend to offer limited frequency response. They are mostly found in the speakers used in toys and small gadgets.
Fiber is the most suitable material for speaker cones, it provides optimal rigidity for quicker response of vibration. It is very rigid and stiff which is desirable from a mechanical point of view. The rigidity of fiber materials provides tight control over the sound vibrations and projects sound in a way that fills the environment.