Kyle Makes A Cardboard iPhone Amplifier

I listen to a ton of podcasts, especially while I’m working. But the speaker on my phone isn’t loud enough to project across the room by itself.

I had seen several passive iPhone amplifiers online (I’d even made one myself a few years ago, but I gave it away), and I knew they worked pretty well. But I wanted to see if you could accomplish the same thing with cardboard.

I started by sketching out the basic shape of the amplifier. Unfortunately I only have one iPhone, and I was using it to take pictures, so I made a cardboard iPhone to show where the phone will go in the pictures. I know, its ridiculous. Just go with me here.

On the iPhone 4S (the one I have), the sound comes out of a speaker on the bottom-right side of the phone. Thus, I drew a channel that would route that sound to a larger round area and direct it forward.


Next, I cut out five copies of this piece, because that stacked up to the width of the iPhone (including the case). I also cut out a rectangle piece for the back, which sealed in the sound and directed it forwards. My youngest daughter Wendy helped me with the engineering.


Using hot glue, I stacked all the pieces together to make the basic shape.


Next I made a front plate, which I decorated with Sharpie to look like a boombox. Because why not? I also added cardboard strips to the side to hide the corrugated edges.


Voila! An iPhone amplifier! Surprisingly, it actually works really well. I suppose “amplifier” is a bit of a misnomer, because it really doesn’t make the sound LOUDER, it just directs MORE of the sound towards you. It definitely SOUNDS louder though.

There are several really nice things about this design:

  1. It’s really cheap. If you have some hot glue and cardboard, it’s basically free.
  2. You can make one for any phone!
  3. You can make it fit a phone that has a case. A lot of the designs I’ve seen online only fit phones that aren’t in their cases.
  4. It’s totally customizable
  5. If you break it, it’s not that big of a deal.

What do you think, guys? Leave your thoughts in the comments below!

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