iPhone 4 Passive Amplifier Case

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By Adam Flaherty
Posted 2011/10/11 @ 2:00 am
Category Computers & Mobile

If you like to ride your bike while listening to music on your iPhone, you’ll find the Horn Bike from Fruitshop right up your alley. This passive amplifier built into an iPhone 4 case easily mounts to your handlebars for hands-free and earbud-free listening. And since it’s passive, you won’t annoy the people you share the road with. [via CNet]

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0 Responses to iPhone 4 Passive Amplifier Case

gaijintendo on October 11th, 2011 at 9:51 am said:

How does making it passive make it less annoying for other people? There is no way it is perfectly directional, and given the nature of sound, for it to be a tolerable level for you while cycling, it will be louder than you need when you stop at lights. To negate that you would require a measure of ambient noise, which is hard to get correct. And even then, sound travels well.

Also, unless you are just strolling through a park on your bike – I really advise people not to blast music whilst commuting. The nearest I have ever been to messy painful death, I was practically oblivious due to listening to a podcast.

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gaijintendo on October 11th, 2011 at 9:51 am said:

How does making it passive make it less annoying for other people? There is no way it is perfectly directional, and given the nature of sound, for it to be a tolerable level for you while cycling, it will be louder than you need when you stop at lights. To negate that you would require a measure of ambient noise, which is hard to get correct. And even then, sound travels well.

Also, unless you are just strolling through a park on your bike – I really advise people not to blast music whilst commuting. The nearest I have ever been to messy painful death, I was practically oblivious due to listening to a podcast.

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Walt Sommers on October 11th, 2011 at 1:43 pm said:

w2we

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Halfvast Conspirator on October 11th, 2011 at 2:42 pm said:

Maybe I should start making bike helmets and exporting them to China

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Walt Sommers on October 11th, 2011 at 2:44 pm said:

Novel . . . But the term “passive amplifier” is an oxymoron. The gadget is an inefficient acoustic transformer (or coupler). It provides no amplification whatsoever. The speaker in the device itself “pushes” a column of air to produce sound. “Pushing” air requires energy – lots of it, and because no energy is being added to the system, it is being dissipated by it. It’s tweeter-sized horn merely directs sound toward the listener and the air couples it to the listener’s ears. The taper and length of the horn are barely suitable for use as a high frequency tweeter – a simple fact of physics based on its size. Nothing states what the sound pressure level might be at the listener’s ears using the iPhone (with the volume turned fully up) but by the time the sound makes its way out of that horn-shaped tweeter appendage and into the air that is already overwhelmed by the roar of city traffic or the incessant 100 to 105 dB chipmunk chirping in my neck of the woods, this “passive amplifier” will go the way of the Ron Popeil Veg-O-Matics and the George Foreman grilling machines.

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