Scrap Wood Cell Phone Amplifier




About: I am a husband, father and DIY'er. My favorite part of DIY is trying to solve the problem!

My cell phone has very poor sound, especially once I put this case on it. So I decided to make a sound amplifier for it out of only materials I had around my shop. This is a very simple build that anyone can do. All power tools can be substituted for hand tools and if you really wanted to, you could change the scrap wood for some very nice exotics. Good luck and I hope you enjoy the build.

Step 1: Materials


-For this build I literally just used scrap pieces I had around my shop. The only guideline I had for it was to make sure the front & back plywood was around 12" long and around 4" tall. Also, that the spacer board was as thick as my phone. This will change depending upon the size phone you have!

-Wood Glue

-Nails (I used 1-1/4" pin nails)


-Spray Lacquer


I used a lot of power tools for this build, but every part could be done with hand tools. It would just take a bit longer.

-Miter Saw

-Nail Gun

-Drill Press




Step 2: Cutting the Pieces

So since this whole project was done from scrap I worked with what I had. First I cut my ply in half. This made each piece around 12" long and 4 " high. For the spacer pieces I didn't measure at all, I just held my back pieces up to the spacer and made sure each piece was the exact length of where it would be attached. You do want to make sure to use your phone as a spacer this way you know that your phone will fit comfortably into the space it's needed. The last thing you want to take into account, which i did not do at first, is where the speaker is on your phone. My speaker is on the bottom right corner, as seen in the picture I did not take this into consideration. I cam back later and cut the piece smaller to allow the sound to move from the phone to the open spaces.

Step 3: Assembling the Back

Now that all the spacer pieces are cut, go ahead and glue and nail them into place. All I did was make sure the spacers and the outside edge of the back board were flush when attaching the spacers. I also used my phone to make sure there was enough space so the phone could move, but not enough that it would fall to the side.

Step 4: Getting Measurements for Phone Area

Now to figure out where the phone would go on the front I just held the front and back pieces together while I laid the whole thing face down.Then I removed the back and this showed me where the phone would be once assembled. I traced the outline of the phone and then gave a small lip on the bottom so the phone won't slide out.

Step 5: Getting Measurements for Sound Holes

For holes that would release the sound I just grabbed some quick measurements of center and then transferred them to the front piece.

Step 6: Cut All Openings

Now it was time to actually cut all my markings out. I started with the holes, I used a 1" Forstner bit on my drill press to cut them out. In hindsight I would make the hole bigger, but you leave and learn. Next, I moved onto the phone cutout. I used my jigsaw to cut a nice rectangle space ensuring to leave the small lip at the bottom.

Step 7: Glue Up

Now that all pieces are cut go ahead and glue the front piece on. I opted not to use nails on this portion so it would give the front a clean look without nail holes. so just apply a small bead of glue and clamp it together.

Step 8: Profiling the Edges

This step is completely optional. After I assembled the amplifier box I thought it would look better if the edges had a slight round over. So I took my router and gave the sides a slight profile.

Step 9: Quick Test

Now that everything was together I decided to give the box a quick test run. It fit the phone perfectly, just enough lip at the bottom to keep the phone snug, while still showing the whole screen.

Step 10: Sand

Since I was happy with the finish I move on to sanding and cleaning up the box. Just make sure to give a light sand to all the edges as well!

Step 11: Finish

Now the box could be left in the bare wood color, but I decided I wanted a nice stain on mine so I put some finish on it. After, the finish dried I gave it a couple spray coats of a gloss spray lacquer.

Step 12: Enjoy

Now that everything was dry and finished I threw in my phone and enjoyed the great look and sound of my scrap wood amplifier!



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    12 Discussions

    Blue Kraken

    7 months ago

    I built one exactly as described it looks very nice on my desk and holds my phone without tipping but I did not notice any change in volume but I am still going to use it as a phone holder.

    1 reply
    OurRuggedWorkshopBlue Kraken

    Reply 7 months ago

    Yea, that was an issue with mine. I noticed a very minimal increase in sound. I thought maybe it was because my phone had a case. But, I also think it is because of the resenance of the wood I used and that the holes releasing the sound could be larger. It does make a decent phone holder though.


    Question 8 months ago

    I have a samsung SMG550 the speaker is up top by the camera flash so would this design work for my phone? picture of my phone modle attached...

    cell phone.JPG
    1 answer

    Reply 8 months ago

    I don't think this specific layout would work. With the speaker in that spot and this layout the sound would just be muffled by the wood.


    8 months ago

    Great job, clear instructions, will try many thanks x

    1 reply

    8 months ago

    Love it! Can you estimate how much it amplified the sound? I'd like to be able to play music for 8 - 10 people sitting at a table.

    1 reply

    Reply 8 months ago

    It probably only amplifies the sound 2x. I don't think that this version would be loud enough in a room with that many people. But, I bet that if the chambers were made larger and the wood use had a better resonance, it could be louder!

    Alaskan Bev

    8 months ago

    This is really awesome! Great photos and narrative - thanks! I have an old LG tracfone that has next to no sound at all. I bought it because it was the only TML phone that the big box store was carrying (triple your minutes for life). I kept missing calls; my phone would be ringing; it could be right in my vest pocket and I wouldn't hear it! Then I read the reviews on that model and the whispering ringer is a universal complaint. That'll teach me! I'm leaving tomorrow and will be out of state for over a month, but this will be my first project as soon as I return!


    8 months ago on Step 12

    Wow. great job. very simple. I wonder how stable this is, and whether you thought about some sort of angular fold-out brace from the back so you could tilt it. I wonder if the current design could get easily knocked over when manipulating the screen.

    2 replies

    I did think about angling it at the end. I wanted to drill a small hole and insert a dowel at an angle to allow it to lean back. But I didn’t have any dowels and since it was a scrap project I feel to buy one would defeat the purpose.

    That makes sense. I have a Moto E 2nd gen phone. Speaker is on top, so unfortunately, this elegant, simple design will not work for me. I'd have to turn the phone upside down and backwards to channel the sound into the baffles.