If you have an old computer speakers, you can turn them into speakers for phone or MP4.

Project Steps

Open your speaker.

Cut the wire that goes from the transformer to the circuit board and connect it to the batteries (9V battery).

You can insert new speakers if you want. I will add this little high-def.

Cut the holes for new speakers or add another box with speakers.

Glue the battery box to the back of speaker box. Watch my speakers test.