I-phone amp.

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Project by jbschutz posted 03-28-2014 02:50 PM 3399 views 13 times favorited 16 comments Add to Favorites Watch
I-phone amp.
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I-Phone Amplifier. A rainy day yesterday, but warm enough to head to the shop/gaarage….but, I needed a project. So, after a little research, I decide to attempt an I-phone amplifier. Four layers of oak, the front and back are 1/4 inch, the second layer is the thickness of the phone and has the sound channels going from the bottom of the phone (where the speakers are) to the “speaker” holes, and the third layer is about 1 inch thick to give depth to the 2 1/4 inch holes. The front three layers are glued up and then hole-sawed out…then the back panel is glued on. The whole box is approx. 4×9 and a bit over 2 inches thick, made from quarter sawn oak and finished with spray poly.
A buddy of mine says that there is likely an acoustic “sweet spot” with regard to materials and “speaker” size. If anyone has any info on this, I would appreciate hearing from you.

-- jbschutz

16 comments so far

View drbyte's profile


847 posts in 5035 days

#1 posted 03-28-2014 03:06 PM

Nice little ‘acoustic amp’! Been planning to do one myself. Cone shaped holes would definitely help I think. I like your oak. Any good hard wood should sound pretty decent I’d think. Maple, cherry, oak etc.

-- Dennis, WV

View WagnerWoodworks's profile


6 posts in 2493 days

#2 posted 03-28-2014 03:11 PM


That looks like a fun project! How does it sound at this point?

When it comes to a “sweet” spot, you’ll have to do a lot of tinkering. I’ve been getting my feet wet in lutherie, and ever piece of wood (even from the same species and the same tree) resonates differently. A good experiment is to take different thicknesses of different woods and tap them with your knuckle. You’ll quickly hear the different tonal properties of the woods. A general rule of thumb is that the denser the wood, the more “bell-like” the tone. Some of the softer woods (cedar, spruce) vibrate better for stronger amplification (and when the resins harden over the years, they sound even better).

If you are having trouble with amplification at this point, you might want to experiment with thinner pieces. Soundboards for instruments tend to be closer to 3/32”, which allows for a good vibration range. Anything thicker resonates too high (or not at all), anything much thinner gets dull like cardboard…

Perhaps you could try (on another piece, not this one) cutting the large holes straight through; on the back side you could then glue a round piece of thin wood (spruce or cedar is great, but anything would work) and on the front, glue a similar piece (perhaps slightly thinner) with a secondary hole in the middle (so it would resemble a large washer). This would create a sound chamber for resonance and amplification.

I can’t promise it would help anything, but it could be fun to try. It would also allow you to use contrasting woods. If you could perfect the design, there might be a good market for it.


-- Jake * Wagner Woodworks * Glenelg, MD *

View Nindwood's profile


134 posts in 2656 days

#3 posted 03-28-2014 03:11 PM

Nice one. They sound really great when you place it on the floor. It gives a lot of depth to the sound. Well done.

-- Narinder, Calgary, Ab.

View TheWoodenOyster's profile


1335 posts in 2908 days

#4 posted 03-28-2014 07:18 PM

This is really cool. I’d love to learn more about this. Does anyone have resources for this?

How is it sounding?

-- The Wood Is Your Oyster

View Sheisserick's profile


124 posts in 2818 days

#5 posted 03-28-2014 08:48 PM

I´ve been planing to make one of these too.

But I was under the impression that you had to make the speaker-holes spherical, to better channel the sounds outward of the speakers?
The best way of achieving this, would be to mount the piece on a lathe, and round out the holes like you would, any other bowl.

How is the sound in your piece?

-- I doubt, therefore I might be

View jbschutz's profile


610 posts in 3664 days

#6 posted 03-28-2014 09:09 PM

Follow up.......After making this one prototype, I am convinced there is a lot of room for experimentation. This one works, but now I wonder how much better it could be with some tweaking. To my untrained ear, I feel like the volume is about doubled and the sound is fuller. At this point, I feel like it is working like a megaphone…channeling the sound directionally toward the area in front of the “speaker” holes. I do plan to try making the back panel thinner, to see if the wood resonates more. I can run it through the planer or over the jointer.
My “electronics” guy wants to do a few tests for frequency response, pressure, etc….whatever all that means, and we may come up with some new wrinkles on the next generation of this thing.

-- jbschutz

View TheWoodenOyster's profile


1335 posts in 2908 days

#7 posted 03-28-2014 09:29 PM

Awesome. Looking forward to the results of the research.

-- The Wood Is Your Oyster

View JL7's profile


8785 posts in 3938 days

#8 posted 03-28-2014 10:01 PM

John, I’ve been thinking about one of these…...very cool. When you make your way up to the Cities, bring it with for a test drive! Keep us posted…......

-- Jeff .... Minnesota, USA

View kiefer's profile


5812 posts in 3640 days

#9 posted 03-29-2014 12:47 PM

Neat looking device and it looks interesting to me .
My wife just got an I PHONE and that looks like a nice little project to play around with .
I have some spruce that may wind up being one of these .

-- Kiefer

View NormG's profile


6508 posts in 3976 days

#10 posted 03-29-2014 01:54 PM

One of my coworkers just brought one of these to work this past week. Husband purchased it off the internet someplace. It reallly does boost the sound of the p[hone and the music does sound great

-- Norman - I never never make a mistake, I just change the design.

View rab23465's profile


5 posts in 2740 days

#11 posted 03-29-2014 03:11 PM

How about a small Chanel coming up from the bottom and the back that would house the connector for the phone. That way you could plug the phone in and have it in charge mode while you play and listen to music .

View Jim's profile


150 posts in 3342 days

#12 posted 03-29-2014 09:30 PM

It works like a folded horn, I saw one that the speaker holes were cone shape.
This is just like having a old bullhorn

-- Measure twice, cut once.

View Roger's profile


21048 posts in 3777 days

#13 posted 03-29-2014 11:42 PM

Rock on John. How bout a lil Skynard and Free Bird.. lol

-- Roger from KY. Work/Play/Travel Safe. Keep your dust collector fed. [email protected]

View JoeinDE's profile


450 posts in 4296 days

#14 posted 04-01-2014 06:42 PM

The one available from Rockler
has these dimensions 3-1/2-inch x 8-1/2-inch x 2-inch
The second pic shows the shape that they use (interesting curvature) for sound wave movement in the wood behind the face plate.

Making it from solid cherry appears to give it decent acoustic properties.


View childress's profile


841 posts in 4514 days

#15 posted 04-01-2014 07:52 PM

this is interesting and looks like fun to play around with.

The only thing I don’t understand is why are there 2 “amplifiers”? There is only one speaker on the iPhone while the other one is the mic… Maybe it’s all connected internally?

-- Childress Woodworks

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