The Basics: Boom Boxes
Boom boxes have become a generic term for any portable audio device with speakers. The word started out as a description of the basic sound they all made--plenty of muddy "boom" to fill a room with no high-end clarity. Technology has improved the sound quality, but the name remains the same.
Boom boxes are commonly confused with minisystems. However, minisystems don't have carrying handles and they only run on AC power, where as boom boxes usually do. And although they can run off an AC power supply like minisystems, boom boxes are given away by their battery compartment.
How to Shop
If you've already started looking at boom boxes in the stores or online, you'll immediately be struck by the enormous variety of styles available. When they first became popular, all boomers looked alike: rectangular boxes with two forward-facing speakers on either end, cassette decks on the front, controls on the top, and of course, the handle.
What has really changed the most in the boom box industry is the choice of features. Every combination of formats is available. Your choice of a boom box should begin by determining what's important to you. Most players have the basics, such as an AM/FM tuner, a cassette player, two speakers, and a CD player. Then, the options take over. The radio can have a digital tuner, which makes preset selection easier. The cassette player can be a dual transport (double deck) that allows for hours of continuous playback or dubbing from one deck to the other. A number of newer units omit the cassette decks entirely.
CD players and CD changers are generally standard issue on boom boxes. A single player, three-disc changer, and even a five-disc changer are options. A changer can use separate disc drawers or use a carousel to store discs. Which one you choose is entirely up to your personal preferences, but separate drawers have always seemed more convenient.
Programmability of track order, track repeat, and random playback are features that add to the usefulness of a boom box. Another feature of interest is a synchronous start that coordinates between the CD player and cassette to start recording. Playback of MP3 and other digital audio files is a relatively new feature in boom boxes, and this will no doubt become more common in the near future.
All features aside, the only thing that really matters are the speakers. Unfortunately, that's usually the worst part of boom box design. Recently, however, small speakers are being designed to output a fuller range of frequencies, and amplifiers are getting more efficient. Inexpensive boom boxes typically save money by skimping on speaker components and design. The best advice is simple: listen before you buy. Unlike other audio products that don't vary much in actual sound quality, boom boxes vary greatly.
http://products.howstuffworks.com/boom-boxes-buying-guide.htm