The Evolution of the Sounder

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This was the original idea, the summer of 2010.  A piece of mahogany with a slot for the ipad, and two scoops top and bottom:  the top scoop to reach the home button, and the bottom scoop to fit on a tummy.  The ipad is plugged into the Bose Wave Radio.  Inserting the ipad into the slot, I wondered if the speakers could be heard through a porthole.

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So, a couple months later, another piece of mahogany with slot and a cylindrical hole.  The slot intersects the hole under the ipad speakers.  This sounded pretty good.   I made four, sold one for $25.   I showed it to a few people, and one said I’d get a better impedance match using a megaphone.  I wasn’t sure what that meant, even after reading up on impedance, but I trusted his expertise. I started to study exponential horns and horns of all kinds.    This led to the next versions.

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This is made of three layers of pine.  The center layer has a cutout of an exponential horn, canted with respect to the front so the opening is centered.  The top and bottom is scooped out as earlier, for the same reasons.  This sounded better than the porthole version.  A more open, fuller sound.

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This version does have the advantage of working in landscape, “theater” mode.  I thought I could do better:

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Here the wood is maple, and the center layer has a folded exponential horn.  The result was terrible.  Possibly the opening to the speakers was too small, or the labyrinth too constrained, but the sound was muffled.

I wanted a one-piece construction that sounded great.   The megaphone idea was worth pursuing.  Why a full megaphone?  Wouldn’t a section do?

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A first experiment with cutting cones.  The speakers feed the cone, and the plug gives the sound something to push against.   The results were very promising.  These produced the most natural sound yet.

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The first FinkPad.   The megaphone is fed by a short pipe from the ipad speakers.  The desktop or tabletop serves to close the horn.  The pad is tilted back to send the sound up.  This was a tiny, tiny, quieter than the first horn, but the quality of the sound was better.  My audiophile friend remarked, “It’s like going from monaural to stereo!”  A 5db gain from holding the ipad in your hand.  Room-filling sound.

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This worked well, but I refined the design so it is easier to manufacture and looks better.

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The production version of the FinkPad.  This version has a slot that works for the iphone speaker and microphone, so the iphone can be used as a hands-free speakerphone.
I now call it the Sounder.

You can purchase a Sounder at www.etsy.com/shop/finkh

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