Verified answer

No single 'driver' can produce all the sounds you can hear. A full-range speaker needs all 3.

When 5.1 soundtracks came out - using 5 full-range speakers raised some problems:

* 5 full-range speakers take up a lot of space

* 5 full-range speakers cost a lot of money

* 5 Woofers take a lot of power to run and your amp must be much, much more powerful than normal to run them.

* 5 sources of bass (the woofers) create complex wall reflections which make the sound throughout the room quiet, loud, boomy, tight - all depending on where you sit

The compromise system that Dolby labs choose to support is this:

* 5 monitor-style speakers (with tweeters and mid-range drivers)

* 1 single woofer in a self-powered box in the corner

This style of system costs a lot less, needs a lot less power to run and arguably creates a better sound experience in a living room.

Among low-priced speakers, you'll find one other factor involved: cost-cutting.

The best-sounding tweeters (with the smoothest frequency response), are often configured in speakers at lower crossover frequencies, like in the 2000 Hz range (so they can produce sound, smoothly, over a wider frequency range). However, using lower crossover frequencies requires tweeters to have significantly greater power-handling capacity. That means they need to be constructed better, and, as a result, cost more.

By comparison, cheap tweeters will usually be smaller in diameter (smaller than 1" --even smaller than 3/4"). The frequency response for small-diameter tweeters is usually less smooth, with sharp peaks, and smaller-diameter tweeters usually have much lower power-handling capacity.

So, the way for a manufacturer to (safely) use a cheap tweeter in a speaker is to configure it using a much higher crossover frequency, like 4500 or 5000 Hz. But that leaves a hole in the frequency response. So, then they add another cheap midrange driver, to fill that gap.

For a manufacturer of inexpensive speakers, this marketing trick is win-win. They know some percentage of buyers, when they see a three-way design, will think they're getting more for their money; when, in fact, using the three-way design allowed the manufacturer to use a cheaper grade of tweeters (which they hope the buyers won't notice).

Our Human ear is capable of receiving audio ranging from 20Hz to 20000Hz called as Audio frequency range.

However, many speaker systems cannot provide faithful output over this wide frequency range. Therefore as an alternative, it is broken into 2 or multiple ranges and each handling a smaller frequency range such as below

Bass - Below 100Hz - Bass - heavy vibrational sound of low frequency - Big sized drums

Midrange 100-2KHz - Normal human voice range including singing - male and female

Tweeter - above 2 KHz (including ultrasonic) - Hi frequency sounds - bird chirping - whistles - some musical instruments - computer generated sounds, etc

Together, we get an experience of a naturally reproduced sounds.

To get a better understanding, as you are aware that through telephone (landlines) the voice of the person sounds different than his/her actual sound. This is because all the frequencies above 3KHz are filtered to accomodate in the telephone transmission circuits. Therefore, the reproduced quality is not good in telephone.

There are many different types of speakers, but the most common are the conventional cone driven loudspeakers. "Most" conventional cone driven speakers will use two or more drivers in order to cover a certain frequency range.

A tweeter is designed to reproduce high frequency's typically above 1khz and because they are not able to reproduce frequency's below that they must be complemented with another driver the reproduces frequency's below 1khz to mid bass frequency's.

These would be considered a two way speaker as they use two drivers to Cover a wide frequency range, where most of the music is played.

A third driver is sometimes added to handle lower bass notes as again it is hard to get a midrange driver to reproduce low bass notes without break up or distortion.

So depending on the design of the speaker you can have one to several drivers. There is a limitation to what one driver can reproduce effectively and then must be coupled with additional drivers to cover a wide enough frequency range that meets the price point and sound the manufactures is trying to come in at.

Do not assume that more drivers or size of drivers will determine sound quality as there are many high end two ways speakers that give incredible sound. There is allot to speaker design that determines sound quality, drivers, enclosure, cross-over design and parts.

Kevin

40 years high end audio video specialist