How to Build a Wooden Phone Amplifier and Charging Station

If you like to play music on your cell phone you’ll find lots to love about this wooden phone amplifier. It provides an attractive platform to cradle your phone while playing music, and it boosts the sounds level by 8-10 dB (decibels) while also distributing the sound around the room using a megaphone style sound enhancement.

As an added bonus, the project includes clever cable routing so that the amplifier can also be used as a charging station. I used black walnut to construct this one, but any hardwood would be fine on this project.

This design should work well for any cell phone that is narrower than 3.5” (including the case) and has a speaker located near the bottom of the phone. I’ve tested with four different models of iPhone and one Android, and the design worked well for all of these phones, producing a similar level of amplification. As you build one for your phone be sure to make any adjustments necessary based on the size of the charging cable connection on the phone end, so that it can be easily routed through the body of the amplifier for charging, as well as the size of the phone slot. I sized the phone slot to be wide enough to accommodate the largest phones on the market today, but in the ever-changing world of electronics it is always wise to measure your phone and size the slot accordingly.

Tools required:

  • Table saw
  • Miter saw
  • Bandsaw
  • Sander
  • Clamps
  • Scroll saw or jig saw
  • First, cut the parts

    Using a table saw, cut the parts to size following the cut list.

    Prepare the Base

    Draw two lines, ½” apart, centered across the top of the base. Then, on one face, draw a line from near each lower corner (1/8” above the base), angling up to an intersection with the lines that you drew in the previous step. This defines the shape of the base. The ½” crown will be the platform that will hold the phone steady, and the angles will form the cone on each side that amplifies the sound.

    Cut the Channel for the Charging Cord

    Set the blade height to 3/4” and make multiple passes to remove the material on one side of the base (not on the top). Use the two layout lines as your guides. Cleanup any sawblade marks with a chisel.

    Transfer Notch Lines to Rear Panel

    The power cord will be routed through the bottom of the rear panel, so you will cut a notch for this purpose using the same procedure as the previous cut. Transfer the lines from the notch on the base to the back panel. This notch is only ½” deep.

    Cut Notch on Back Panel for Cord Clearance

    How to Build a Wooden Phone Amplifier

    Set the blade height to 1/2” and remove material on the bottom of the back panel (do NOT do this on the front panel) to provide clearance for the cord to exit the amplifier.

    Make Angled Cuts on Base

    How to Build a Wooden Phone Amplifier

    Using a bandsaw, make the angled cuts on the waste side of the angled lines, leaving the lines.

    Sand to Lines

    How to Build a Wooden Phone Amplifier

    Using a belt sander or random orbital sander, remove the saw marks from the work piece, sanding to the lines.

    Cut Slot for Phone in Top Panel

    Wooden Phone Amplifier

    Using a scroll saw or hand-held jig saw cut a 5/8” x 3-1/2” opening in the top panel. The slot should be centered on one edge of the top panel. A width of 3-1/2” should accommodate most cell phones, but you can customize this width to fit the exact size of your cell phone (including the case if you use one).

    Alignment for Assembly

    How to Build a Wooden Phone Amplifier

    Be sure that the back panel is positioned with the notch down, and that the notch on the back panel is aligned with the notch on the base. This will allow smooth travel of the charging cord through the base.

    Glue-up

    Apply woodworking glue to all joints. With butt joint joinery like this I like to let the glue set up for a few minutes before applying clamps. This allows the glue to start to grab a bit, and the assembly is less likely to slide under clamping pressure. Use a screwdriver and rag to remove glue from corners inside the assembly.

    Cut Tapered Ends

    How to Build a Wooden Phone Amplifier

    After the glue cures, scrape off excess glue. Then cut each end to a 45-degree angle, starting at the rear outside edge at each end and tapering toward the front of the device. Final length should be about 11”, long point to long point, with the cord and phone slots centered on the length. This cut can be made on a miter saw, table saw or bandsaw. If you do not have a power tool that has enough capacity to cut 3-1/4”, then you can easily make the cuts using a hand saw.

    Sand Body

    How to Build a Wooden Phone Amplifier

    Sand thoroughly, gently rounding over the sharp corners. Do not round over the corners too much, however, as you’ll lose the angular geometry that defines this piece’s appearance. Also, hand sand around the perimeter of the cell phone slot so that it is not sharp.

    Finish

    How to Build a Wooden Phone Amplifier

    I applied a couple coats of walnut oil, but you can use whatever finish that you prefer.

    Using as a Charging Station

    How to Build a Wooden Phone Amplifier

    Route charging cable up through the bottom and up through the channel where it connects to the phone. The cord then runs out the slot through the back panel so that it can sit flat without interference from the cord.

    Discussion
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    50 Responses to “How to Build a Wooden Phone Amplifier and Charging Station”
      • Customer Service

        Hi Tom. I haven’t tried this but as long as the speakers are in the lower location, in theory it should work. I would expand the entire project to achieve better proportions, however, and not just the slot.
        Thanks
        Paul-WWGOA

        Reply
    1. Inez

      What happened to the PDF version? I prefer to download and view later, offline, in my workshop?

      Reply
      • bryan

        What i do is print, once the box pop up change from printer to save as pdf. It will save the page your viewing as a pdf on your pc/mac…
        If it auto prints then you’ll have to default your print temporally to pdf printer. Works for me. Hope it helps.

        Reply
    2. Antonio C

      Great project for a Christmas present! Very simple, making possible for anyone that knows how to use a miter and a jig saw. Do you know if the lower of the wood density, does amplified the sound better? Thanks!

      Reply
      • Customer Service

        Hi Antonio. Thanks for the feedback. I don’t know exactly how the wood density will affect the sound amplification. That’s a good question. I tested with hard maple and walnut, and didn’t notice a difference between those two, but they are not vastly different in density. If you took it to a greater extreme, like basswood vs. Brazilian Walnut, I don’t know what the result might be.
        Thanks
        Paul-WWGOA

        Reply
    3. John S. Brunel

      Built another design but I think I like this one better, looks better, thanks for posting.

      Reply
      • Paul Mayer

        That’s cool, Craig! I’d love to see a picture of the students with their final project. If you send one to us at wwgoa we would love to post it on our FB page.

        Reply
    4. Al Patton

      This device could potentially be improved by adding a sloping bottom section so that the sound channel more closely approximate an exponential horn. You would gain an increase in sound pressure. The device as built has only one sloping member; think about adding a second sloping surface. If you are unfamiliar with exponential horns then visualize a trumpet or trombone. As in any device that uses this principle, larger is better. The lowest frequency that can be faithfully reproduced is a function of the diameter of the opening or in this case the diagonal.

      Reply
    5. Joel

      I was thinking of using purple heart it is hard maybe it will give it more sound. If anything it will look good

      Reply
    6. TRACIE JACKSON

      I love this project and I make things to sell at the flea market. Can I add this to my compliment.

      Reply
    7. Mark D Colbert

      Great pictures and descriptions of what you are doing. This is important for a beginner wood worker like me . I will try this one THANKS!!

      Reply
      • Customer Service

        Hi Chase. It depends on lumber pricing in your area, and what species you decide to use. There is approximately 1 board foot of wood used in the phone, so here in MN that will cost you anywhere from $.50 to $20 depending on what wood you choose.
        Thanks
        Paul-WWGOA

        Reply
    8. TRACIE

      I asked this question before however i haven’t seen a reply. Is it ok to copy your plan and sell the finished project at craftshows and flea markets

      Reply
      • Customer Service

        Hi Tracie. Yes, that is fine. Thanks for asking. We would love to see a picture of these on your show table if you’re up for sending one.
        Thanks
        Paul-WWGOA

        Reply
    9. Eddie

      Looks great especially for people that has trouble hearing the music or the phone conversation.

      Reply
    10. Brenden Thomas

      I’m doing this for a project and I wanted to see if you can tell me the front,top and side dimensions

      Reply
      • Customer Service

        Hi Brenden. Here you go. Front: 3″ wide x 3-1/4″ tall
        Side: 5-3/4″ wide x 3-1/4″ tall
        Top: 11″ wide x 4″ deep
        Thanks
        Paul-WWGOA

        Reply
    11. Dominick Hewitt

      I made one out of MDF, as a prototype, it works great. Now for the hardwood version. Thanks

      Reply
    12. jeffeu

      The “tech support’ didnt help me wih my hard wood problems and told me to go

      Reply
      • Customer Service

        Hello. Please let us know what your question is and I can send it to our expert for an answer for you.
        Thanks
        Jean-WWGOA Video Membership

        Reply
      • Customer Service

        Hi Geff. Please let us know what your question is and we will send it to our experts to answer.
        Thanks
        Jean-WWGOA Video Membership

        Reply
    13. slpangborn

      Clever accessory for phone and a great simple project to do that produces a very useable product, great job!!

      Reply
    14. Kim Donahue

      Thanks Paul.
      Just finished mine. Love it.
      Fun, quick and it looks and works great.

      Reply