DIY phone speaker
Then, use push pins as feet to stabilize your speaker. Make sure to stick the pins on the edges of the tube, away from your phone so they don’t scratch it. You can finish up by coving the tube in colorful tape, like I did, if you wish.
To use the speaker, slide the end of your phone that has the built-in speaker (usually the bottom) into the slit. Here are some more DIY speaker ideas.