If you've got an old, seldom-used cooler lying around your garage, you may turn it into a musical conversation piece. With a small power source, such as a lawn-mower battery, and car stereo parts, you can make a boombox cooler that plays music and stores CDs, headphones, MP3 players and other musical accessories.
Research waterproof car and boat stereo components. If you're planning to use your boombox cooler on a boat, near a pool or anywhere where exposure to liquids is likely, opt for marine-quality stereo equipment. If you don't plan to get your boombox wet, regular car stereo components will do.
Evaluate the stereo models in terms of the type of cooler you're using. The size of your stereo receiver and the size and number of speakers you use depends on the size of the cooler in which you'll be installing them. A large industrial cooler accommodates large woofers and tweeters, while a more-modest system is best for compact coolers. Choose appropriately sized components.
Trace an outline of your stereo receiver on the lid of the cooler. With the cooler closed, place the stereo receiver backside down on top of the cooler. Hold the receiver firmly in place as you trace around it on the cooler lid with a permanent marker. Use an electric hot knife to neatly cut a hole in the lid using the tracing as your guide. Ensure that the slot is large enough to snugly accommodate the receiver.
Remove the face cover of the receiver. Insert the head unit face-side-up through the slot in the lid and replace the face cover. Gently slide the unit down into the slot until it's flush with the top of the cooler lid. Add a few beads of silicone sealant under the edge of the face cover all around to adhere it to the cooler's lid.
Determine where you wish to place the speakers in the cooler: in the front, back, sides or a combination thereof. Each speaker has a front cover that slightly extends beyond the width of the actual shell, like a "lip." Measure around the widest part of the shell — not around the cover, or lip — to determine the size of the cuts to make in the cooler.
Draw the exact dimensions of your speakers onto the outside of the cooler. Use the permanent marker for clearly visible outlines. For round speakers, use a compass to create perfectly measured circles. A ruler or tape measure is required for square and rectangular speakers.
Cut out sections of the cooler to accommodate the speakers. Carefully and evenly cut your tracings from the sides of the cooler with the hot knife. Make certain that the speaker cutouts snugly accommodate the speakers and that the speaker lip rests flush against the outer surface of the cooler. Add several beads of silicone gel to secure.
Place your battery inside the cooler and install all wiring connections. Use silicone gel, double-stick tape, fabric fastener or duct tape to secure your power source to the inside of the cooler. Connect the speaker wires to the receiver, then the receiver to the power source. Turn the unit on to test it and troubleshoot for any poor wiring connections.
A cooler converted into a boombox isn't intended for storing or transporting foods, beverages or other liquids. To prevent personal injury or damage to the unit, don't place ice or liquids inside of your boombox cooler.