A good speaker will make peaks and troughs feel delicate, making the music or cinematic soundstage seem to extend around you. This is known as imaging.
How Speakers Work
Speakers turn electrical signals into mechanical vibration that creates air pressure waves, the fundamental building blocks of sound. The vibrations are transmitted through a medium—the air—to special hairs in the human ear that change the mechanical energy into electrical impulses that the brain interprets as audio signals. The basic principle of how speakers work is surprisingly simple.
When a signal is fed to a speaker, it starts to move its cone in and out of the magnet. The movement of the cone is what creates the sounds we hear, and the speed at which it moves is controlled by the electrical current coming from the amplifier or stereo. When the signal stops, the movement of the cone comes to a stop and the vibrations are absorbed by the surrounding environment.
While speakers do a great job of turning electrical energy into acoustic output, they can’t reproduce all frequencies equally well. To produce the highest frequencies, a small driver called a tweeter is used. Middle frequencies require midrange drivers while the lowest frequencies are reproduced by a larger speaker known as a woofer. In multi-driver speaker systems such as hi-fi home theaters or Hi-Fi audio components, there is a piece of passive electronics called a crossover that helps to direct components of the electronic audio signal to the drivers best capable of reproducing them.
The physical specifications that describe a speaker driver are called Thiele and Small parameters, named after two professors who developed their theory of electric-acoustic modeling. The most important ones are frequency response (a plot of amplitude vs. frequency); distortion (measured using several different test signals); stored energy; sensitivity; and impedance, which is the geometric sum of the resistance of the voice coil wire windings plus its inductive reactance at a given frequency.
Since the impedance of a speaker can increase as the frequency being played increases, its basket—the enclosure that houses the cone, coil and suspension—needs to be made from rigid materials to prevent unwanted rattling. The basket must also be designed to be acoustically neutral, avoiding resonant modes and resonances that color the sound produced by the speaker.
The Driver Speakers
The part of a speaker that relays the electrical signal and transforms it into sound. In golf, it’s also called a number one wood, because the driver is used to hit low drives from the tee. People who offer to be “The driver” often say they’re better drivers than others, so that they can safely take people on rides to concerts or business meetings. These example sentences are selected automatically from various online news sources to reflect current usage of the word ‘driver’.
The Voice Coil Speakers
When alternating current from your speakers amplifier flows through the voice coil, it turns into an electromagnet. The coiled length of wire is wrapped around some kind of magnetic metal—usually iron—creating north and south pole orientations. When a speaker is energized, the polar orientations are switched back and forth, drawing the coil toward the magnet then repelling it away from the magnetic field. The changing of the polar orientations causes the cone to move back and forth across the diaphragm, creating vibrations in the air that we perceive as sound waves.
The earliest voice coils were wound on paper bobbins, which worked fine for modest power levels. When higher-power amplifiers came on the scene, aluminum bobbins quickly showed their limitations. The material efficiently transfers heat from the bobbin into the adhesive bonds of the speaker, thermally degrading or even burning them. The motion of the aluminum bobbin within the magnetic gap also generates eddy currents that increase its temperature, further hampering long-term reliability.
In 1955 DuPont developed Kapton plastic film, which did not suffer from aluminum’s drawbacks and was widely adopted for speaker voice coils. More recently, alloy 1145 aluminium foil has replaced paper bobbins in most hi-fi loudspeakers. These dark-brown films withstand brutal thermal and mechanical stresses but are expensive to manufacture, and have a tendency to soften when heated.
A more durable solution is a thermoset composite of glassfibre cloth impregnated with polyimide resin. Hisco P450 combines the best qualities of these materials and is designed to tolerate severe simultaneous thermal (300degC) and mechanical stresses.
The material technology of the form, the coil winding, the collar, the lead-out wire and the adhesives that bind it all together are critical factors in making a voice coil that performs the way you want it to. Copper is the most common wire used in speakers, and it offers high sensitivity and versatility at a cost-effective price. To reduce the mass of a voice coil, copper-clad aluminum wire is sometimes employed, although it has less conductivity than standard copper wire.
The Cone Speakers
The cone is a speaker’s physical representation of sound waves and it’s the part that creates the sounds you hear. It can be made out of many different materials but typically it’s a rigid material such as paper, polystyrene foam or PET. The exciter of the speaker sends electricity into the flat surface which then vibrates, producing sound. A speaker may use a cone or a diaphragm but the most common is a concave diaphragm. This is a shape that’s very effective at creating sound waves because it can be used to produce high frequencies and low frequencies equally well.
Speakers are not required to know the technical details behind their audio equipment but if you’re going to be spending any significant money on speakers it’s always good to have some basic knowledge before you make that decision. A little background knowledge can help you avoid snake oil salesmen and find the right speaker for your budget.
A speaker is a person who addresses an audience and delivers a message. They can be anyone from a politician to an expert in their field or even a member of the public. The role of the speaker is to present facts and opinions clearly and concisely. They should be able to engage their audience and evoke emotions in their listeners. They must also be able to answer questions from the audience and remain impartial.
What’s Next?
There are many different types of speakers, all with their own unique skills and personalities. There are keynote speakers who inspire and motivate, while there are business speakers who help businesses develop their teams. Then there are speakers who talk specifically about the future, such as futurists or visionaries. They can offer insight into trends and potential outcomes of various scenarios, which is helpful in a fast-moving and volatile world.
Speakers play a crucial role in our society, from politicians to corporate leaders. They can influence policies, promote ideas and build awareness of a particular subject. Speakers can also play an important role in education, where they can educate students and teachers on specific topics.