ON TO THE WOOFERS AND TWEETERS
Since the audio signal is broken up into different frequency ranges to be sent to different speakers, it only makes sense that the speakers be designed to handle those frequency ranges. That’s where woofers and tweeters come in. A woofer is a speaker designed for low-frequency sounds and a tweeter is a speaker designed for high-frequency sounds.
At a glance, the main difference between woofers and tweeters is that the woofers are a lot larger than the tweeters. A good woofer might be 12 inches in diameter or more. There are a couple of reasons for that. First of all, the speaker has to move slower and the diaphragm (the speaker cone) has to move farther to create the sound wave. Secondly, the speaker must produce a higher volume of sound, as low frequency sound waves don’t travel as well as high frequency ones do and are much more likely to dissipate and be absorbed by surfaces they come into contact with.
The speaker enclosure and the woofer interact with each other; so the speaker enclosure is usually designed specifically to match the woofer. There are several types of designs, but the two basic categories are a sealed enclosure and a ported enclosure. Sealed enclosures try to trap the sound coming off the back side of the speaker, providing the cleanest, crispest bass sound. However, the sound volume is lower.
Tweeters do not interact with their cabinets at all, and at times are used without a cabinet. While the construction is similar to a standard electromagnetic speaker, they usually use a dome-shaped diaphragm in place of a speaker cone. These are referred to as “dome tweeters.” This diaphragm can either be made of plastic, plastic impregnated silk, aluminum or titanium. Each material type produces its own unique sound characteristics.
Since tweeters are extremely small, they don’t produce a lot of volume. To help this, many are attached to a horn. This horn resonates or vibrates with the tweeter, mechanically amplifying the sound that it produces, in much the same way that a trumpet or other brass instrument amplifies the buzzing of the musician’s lips.
SPEAKER SPECIFICATION EXPLAINED
Frequency response :-
Frequency response describes the range of audible frequencies the speaker can reproduce between 20 Hz (deep bass) and 20 kHz (a piercingly high frequency), which is considered the range of human hearing. In reality, our hearing does not typically extend up to 20 kHz (especially as we get older), and bass frequencies below 30 Hz tend to be felt more than heard.
The most meaningful ratings include a plus/minus deviation (±3 dB is typical), which indicates how far the sound deviates from a neutral or "flat" response; the lower the number the better, although in practice, speaker placement and room acoustics greatly affect what you hear. Still, the number at the lower end of the range gives you an idea of how low the speaker can play. For example, a rating of 50Hz - 20kHz ±3 dB means you will need to add a separate subwoofer if you want to reproduce the deepest bass.
Sensitivity describes nothing about the sound itself but will give you an idea of how efficient a speaker is — that is, how loud it will play when fed a standard test signal and measured at a specific distance (usually 1 meter). Sound-pressure level (volume) is expressed in decibels: the higher the number, the higher the efficiency. Numbers in the mid-80s are typical, while anything over 90 dB is considered excellent.
Impedance sheds no light on sound quality but tells how much strain the speaker places on an amplifier. The lower the number, the more strain; most speakers are rated at 8 ohms, which is considered an easy "load." If you come across 4-ohm speakers, just make sure the amplifier driving them can handle the extra load (most good quality amps can).