When shopping for speakers, one term you will encounter frequently is full-range. This term is intended to let the buyer know the speaker is capable of reproducing all -- or most -- of the audio frequencies humans are capable of hearing, without the need for additional equipment. In comparison, some speakers, such as subwoofers and micro-cube speakers, are only capable of reproducing a limited range of frequencies.
Understanding Human Hearing
To understand what full-range means, it helps to know something about human hearing. Sound is measured in units called hertz (Hz), defined as the number of times a sound wave rises and falls from its highest to lowest points in a single second. The higher the measurement, the higher the sound. Humans are generally capable of hearing sounds ranging from 20 Hz on the low end to 20,000 Hz on the high end. To help put this into context, the lowest note on a grand piano is around 33 Hz, and the highest note created by a violin is around 16,000 Hz. A full-range speaker should be capable of reproducing most -- if not all -- of these frequencies.
Most full-range speakers include a dedicated tweeter, which is the component that reproduces the highest frequencies. They are responsible for reproducing frequencies from approximately 2,000 Hz to 20,000 Hz, although some can go much higher. A tweeter is typically the smallest component in most speakers, and may look like a small dome, a rectangular horn or a small sheet of film protected by a grill.
In a typical speaker with three driver components, the midrange driver is responsible for reproducing the frequencies between approximately 300 Hz and 2,000 Hz. This is where most of the frequencies in the human voice can be found, as well as most of the sound created by musical instruments. In most full-range speakers, the midrange driver is cone-shaped and made of paper.
Also known as woofers, bass drivers reproduce the lowest frequencies in the audio spectrum. The woofers in most full-range speakers are responsible for the frequencies from approximately 40 Hz to 300 Hz. This is where you will find most of the notes created by the bass guitar and kick drum, as well as those created by bass orchestral instruments. The bass driver is generally the largest component in any given speaker, and like the midrange driver, is usually cone-shaped and made of paper.
Some smaller full-range speakers only include two component drivers, with a single driver handling the bass and midrange frequencies. This is typically referred to as a mid-bass driver. The low end in such speakers usually cuts off around 100 Hz, meaning the bass will not be as deep as speakers with dedicated woofers.