Unplggd reader and MIT Architecture grad student, Noel Davis, found himself motivated to contact us after seeing Joel's DIY digital Lomography camera project, sending us his own impressive handiwork. Like Joel, Noel was lured by a beautiful piece of tech: the iVictrola's repurposed antiquated design is indeed a beautiful marriage of form and function. But the $1,000 price tag was out of Noel's budget, so he looked to an affordable (and more creative) solution...one involving a laser cutter, aircraft plywood and his own unique design!
Starting from a photo I'd seen of the iVictrola, I spent a Saturday scouring antique shops for a similar phonograph horn. Unfortunately I wasn't able to find one, and a search on eBay showed a few, but they were way too pricey for me. So I decided to make my own. I knew right away a circular cone would be too difficult, so I settled on a square one.
I did some reading on Wikipedia about horn loudspeakers, which are used to amplify the sound from a small driver (like the needle of a phonograph or the tiny speaker in a cell phone), especially the low frequencies. The article suggested that the cone should expand exponentially, so I made a test out of paper with the cross-sectional area increasing by 30% for every centimeter of the cone. The shape looked great, and it went together easily enough with scotch tape, but it didn't amplify the sound at all when I held it up to my phone. I think the paper was too flimsy.
Encouraged by the first attempt, I decided to make a similar cone out of wood. Instead of a straight cone, I opted for a more sculptural question mark shaped, like something out of Dr. Seuss, and similar to the phonograph horns I'd seen. The geometry was quite a bit more difficult, so I spent a day modeling the design in SketchUp to create the cut templates. Then I used a laser cutter (I'm a graduate student in MIT's Architecture Department, so I have access to some pretty nice tools!) to score and cut my templates out of 1/64" thick model aircraft plywood.
I bent and glued small strips of basswood along the edges of each side panel, and then used those to attach the top and bottom. Unfortunately the curve on the bottom panel was too tight for the plywood to bend, so I had to end up cutting that piece into smaller strips (you can see the facets on the bottom in some of the photos). It took an entire day and two rolls of masking tape to glue the cone together. When it was finished, I held the small end up to my phone to test it, and the amplification was immediately noticeable. The horn also gives the phone a nice hiss-crackle-pop sound like an old record player.
With the horn done, I made the base as a stack of laminated plates. This allowed me to leave a channel in the middle for the sound to pass from the phone's speaker into the bottom of the cone (shown in red). I cut out the base parts on the laser cutter, glued them together, and lined the iPhone dock with felt to seal around the speaker and keep the wood from scratching it.
That's it. The whole project took about 3 days, and $40 in materials (1/64" plywood is very expensive). I'm really excited about it. hough it's not as loud as I'd hoped, the old-timey sound is great, and it looks really cool on my desk!