Basic Understanding of the Speaker and its Parts
Understanding the parts of a speaker is very important as it helps to show how speaker specifications compare to each other. A complete understanding of how loudspeakers are built internally provides enhanced knowledge that can be visualized to explain what differences matter between different types of loudspeakers for a space.
Basic Speaker Parts
A loudspeaker is defined as a sound driver or speaker driver. The driver is a key element of the speaker system as it converts the line-level voltage of the speaker amplifier into sound by pushing and pulling the air molecules in the waves that the human ear cares about as sound. Drivers can be made from a variety of materials, such as reinforced paper cone shapes, metal dome diaphragms, or carbon fiber elements. All inside a metal coil.
A speaker unit would not exist without an enclosure. The enclosure can be a dedicated wooden or plastic box for stand-alone speakers or a cavity created between drywall and concrete walls for in-wall speakers.
The size of the speaker enclosure should be related to the size of the room. Speakers designed for much larger rooms won't sound good in small rooms. The size of a speaker enclosure determines the amount of air movement and therefore the sound energy these speaker systems can produce in a room.
Speaker enclosures come in many forms, such as bass reflexes or ported enclosures with holes in the front or back that allow more bass to leak into the room. To produce more accurate sound well-designed sealed enclosures tend to work better.
Well-made speaker enclosures use reinforced structures called braced enclosures to ensure that the enclosure vibrates as little as possible. Enclosure vibration adds undesirable coloration to the sound, especially at the enclosure's resonant frequency. This tends to be closer to the upper bass frequencies.
The driver diaphragm is secured to a metal basket with a flexible surround at one end and a spider at the other end. The entire diaphragm/voice coil is free to move according to the movement the voice coil generates in response to electrical signals.
Faster, higher-quality driver diaphragms use aluminum or titanium. These are mainly used for advanced tweeters. However, inexpensive materials such as reformed silk, paper, and certain plastics also produce great sound.
Understanding of Speaker:
It is often defined as nominal power (Watts RMS).
Impedance refers to the resistance a speaker presents to an electrical signal. The lower the impedance, the more power (current) the speaker draws from the amplifier for a given output voltage.
This means that a 4-ohm speaker will load more amplifiers for the same output signal level than an 8-ohm speaker. So don't buy speakers without considering the AV receiver or amplifier specifications.
One of the most important speaker specifications is speaker sensitivity. This is specified in decibels (dB) using a 1-watt test tone measured 1 meter from the speaker.
This means that sensitivity affects how much power the system needs to operate properly within its setup. The average speaker sensitivity is around 87-88 dB. This measure is logarithmic. This means that a 3dB reduction in speaker sensitivity would require doubling the amplifier power to produce the same volume in the room.
Speaker Frequency Response
Given that the speaker frequency response is not constant over the entire range, the response is often specified within ±3 dB of dispersion. This ±3 dB represents reasonable consistency. Some manufacturers also specify an extended frequency response at ±6dB, but that doesn't make sense in itself, as you'll need up to 4x the amplifier power for the bass of the speaker's response for anything as loud as the treble in the range.
For example, a speaker with a specific frequency response in the range of 40 Hz to 22 kHz, ±3 dB could be considered to have pretty good coverage from good bass to high frequencies just above the upper limit of average human hearing.
Speaker dispersion (H x V) specifies the speaker sound radiation pattern at various angles. It tells you how the sound changes as you move away from the speaker's main axis. If you look at the specifications of the speaker box, you will see the nominal angle of high-frequency dispersion in the horizontal and vertical planes.