A subwoofer emphasizes those frequencies on the low end of our hearing spectrum. Adding a subwoofer adds a certain bigness or dimensional depth to the overall sound. Some systems have an integrated subwoofer or an output for an optional subwoofer. Usually, external subwoofers come with an integrated amplifier while integrated units have a separate amp channel. The place for subwoofers is usually on the floor in a home audio system.
Most systems have an output port for an additional subwoofer.
How high or low a system is priced reflects the quality of the components and overall accuracy and clarity of the sound. Because of the mere nature of minisystems and the way they are built, when you buy any minisystem, you get a lot for your money. You re essentially getting a number of different components all nicely fitted into one unit. They are designed to provide optimal performance within a given price range. One of the major determining factors of price is how many speakers a system comes with.