I work in an environment where a typical stereo/ boombox will not work very well.................maybe one local fm station.....and if your not country....well. A car radio could help here.
Here is what you need:
Find a car stereo that works and then find the wiring diagram on the internet.
Find a working computer psu.
Have wire strippers.
Speaker wire or small wire.
Power wire or small wire
wire nuts....or black tape
In our case we had 4 decent sized Ford automotive speakers with big magnets on the back. The first thing to do is find out which terminal is negative and which one is positive. It is easily done by temporarily attaching wires to each speaker terminal and touching any 1.5v battery to each stripped end of the wires. We used a AA battery. While looking at the face of the speaker, touch the battery wires to each end of the battery. If the speaker felt moves from the outside edges of the speaker frame toward the center, the polarity is backwards. Natch, if it looks like it's spreading from the center outward, it's correct. Mark the negative and positive as near the speakers' terminals as possible. If a wire was touching the positive end of the battery when the speaker felt was moving outward, mark that terminal positive.
Now look at the radios wires. There is usually a molex plug with the wires snipped off. If not you will need to buy one or improvise. There will be mating colored wires and one will have a stripe.Eg. gray and gray with a stripe. In our case the wiring diagram said the striped wire was negative.Most radios will have 4 pairs of matching speaker wires. To stay consistent, if you use speaker wire, the striped wire will go from the negative speaker terminal to the striped (neg) radio wire and the non striped from the pos. speaker terminal to the solid wire.
Now the power. On the power supply, use a paper clip or some other jumper to jump the black and green wires on the motherboard molex connector. They are near each other in the middle of the molex connector. Now on the psu's power molex connectors ( the ones that we connect all the drives to) , test which yellow black wire combo( on the same molex) gives 12 volts. ( all of them, the mobo connector is less). Snip a yellow wire and a black wire, after confirming the voltage.This psu black wire connects to the radio's black wire. The yellow wire conects to the radios red and yellow wires. The trick here is that most of the radios yellow wires are not really yellow. It is a trial and error to see which of the available three wires is really the yellow wire. They are usually some form of dirty white or tan. The radio's red and yellow wires are battery and ignition.
Plug this in and the radio should work save for needing an antennae. There could be an on/off switch on the psu.
In our case we bought a regular antennae wire that plugs in and a cheap antennae. AM radio still does not work because our radio is in a steel building that is inside of a steel building that has all kinds of high voltage power lines in the area. AM radio needs to be outside to pick up well. We managed to get our antennae outside of the building and get very good results as compared to a boombox type.
If you have a very old radio, an ac/dc wallwart will work. Test the leads while plugged in. If the voltage reads negative,on your multimeter, your black test lead is on the positive. Newer radios cut out when all the speakers are hooked up or if you turn the radio up too loud, while using a wallwart.
Our speakers were attached to big steel beams using only the magnets built into the speakers.