Android Passive Amplifier Speaker




About: Idea Man, Jack of all Trades, Master of None. Have gun will travel. Sometimes nothing is a real cool hand. Shoot the three and play no D.

I made this over the course of a couple of days, pretty easy, just be sure to measure twice and cut once!

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Step 1: Getting Started

Cut 4 pieces of select pine (free of knots) to the same dimension. This will vary by phone size and cases etc. I measured with case as I have no plans to disassemble my case with each use.

Step 2: Making Holes

I used a 3 1/4" hole cutter on 3 of the pieces. After I cut one hole, I clamped to the next piece and drew down the drill press to mark the next piece. I then drilled that piece and did the same procedure with the third one. This help ensure the 3 holes line up when gluing and minimizes sanding of the sides later.

Step 3: Glue the 3 Hole Pieces

I next glued and clamped the 3 pieces with the holes and let set for the night.

Step 4: Routing the Sound Channel

Turning the 3 piece glued assembly face down I traced my phone to a depth I felt would hold it securely without it being too wobbly when inserted into the final project. I clamped the work piece down to my bench and slowly and carefull routed a depth equal to the thickness of my phone with case. I then, with a pencil, manually drew the channel from where my phones speaker was to the sound holes in the work piece. I then carefully routed that channel out. Before moving to the next step, I used a drum sander on my drill press to sand the cut circles smooth.

Step 5: Sanding and Gluing the Back Piece

The next step was to glue the back piece on the work piece. First I sanded the face to make it easier than trying to sand it after the glue up. I clamped and let sit for the night. Be sure to use a wet cloth to wipe out any glue in the speaker that squishes out. Afterwards, I palm sanded all sides smooth. I finished with several coats of spray polyurethane.

Step 6: Finished Speaker

The finished speaker amplifies sound quite well. Its a handsome looking block of wood with great pine graining. Serves the purpose when I use it to just play music for myself without a crowd or party. I have attached a video but it doesn't do justice to the sound amplification.

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12 Discussions

tyler hunt

4 months ago

hi im a student in horsham england and would like to know how you get these amazing ideas

1 reply
Radio Dudetyler hunt

Reply 4 months ago

Tyler, thanks for your interest. Many ideas arent mine originally. Ive been inspired by Pinterest for many of my ideas, both big and small. It has a wealth of ideas and pictures and is searchable. I see what others have done and alter for the better or revise how or what i was going to do.I try to maintain the integrity of the original piece as much as possible in my radio to wine bar conversions. I also take my time and think through the process as much as possible. Hope this helps!


2 years ago

I'm making one of these and these instructions were helpful.


2 replies

3 years ago

Nice job and nice idea!
Why not attaching an audio file or YouTube video where you show the effect of the speaker? Is it actually amplifying?

6 replies
Radio DudeFileBravo

Reply 3 years ago

Thank you! Im good with wood but not so much Youtube etc. I do have a video so maybe if I can upload to youtube, ill imbed it to my instructable.


If you can text the video to me I can upload it to youtube for you and you can imbed it :)


Thanks Jonathan. I actually looked for it on my phone but its on my computer at home. I did go to Youtube so I think I should be able to figure it out. If not Ill follow-up with you. BTW, there are example videos from others on youtube so you can hear the actual results of these type of speakers.

Radio DudeRadio Dude

Reply 3 years ago This is the youtube link to a short video of the speaker in action.