Tweeters produce the highest frequencies in sound, typically anything above 2,000 Hz. Usually located at the top of the speaker, tweeters come in different shapes (detailed below) and sizes. Generally speaking, the size of the tweeter is not as important as the shape. But, for some guidance, consider that a larger tweeter (measured by diameter in inches or millimeters) will likely be louder and able to disperse sound over a larger area.

The woofer is the driver that is responsible for low frequency sounds and bass - crucial for well-rounded, booming sound. It is the biggest driver in size, and is usually shaped like a cone. When reviewing different bookshelf speakers, you will often see a measurement in the product name, starting as low as 4” and ranging to 6 ½” or more. This measurement refers to the diameter of the woofer. A general rule of thumb is a bigger woofer means louder, more powerful bass. But, as with any speaker metric, this number alone doesn’t describe the loudness of the speaker and should be taken into consideration with other measurements such as sensitivity, which describes the loudness of a speaker per watt.