"Griffin reckons the AirCurve’s sound amplification"...

...if it's doing any kind of amplification i'll be most impressed. Also, if so, James Randi wants to talk to them about the 1 million dollars that's burning a hole in his pocket...

All it can do is change the shape of the output to allow for a louder sound over a smaller area. The total energy output will be the same (will be less due to more components introducing more inefficiency)

Jeez! It doesn't amplify at all. It does an impedance transformation. If you want to write about technology at least learn something about it first.

Correct link; http://www.griffintechnology.com/products/aircurve

It's under Iphone accessories, and the article starts up with it being for an ipod before changing to iphone...not the average mactard will know the difference oh fuck that's done it..

First paragraph mentions iPods, yet they have no speaker, unless you've bought one of the new 2nd Gen Touches. Later on, the story mentions Jesus Phones. Can we have some compatability info? :D

For those of you who are interested, this works by using a mathematically calculated exponential horn. This is the most efficient shape for a amplifying horn, which produces an amplified sound due to the resonance of the column of air (so no batteries required). By adding such a horn to the standard iPod speaker, it actually makes the way in which the energy from the speaker is converted into moving airwaves more efficient.

Exponential horn technology that was originally put into wind up gramophones manufactured by by HMV (c. 1928) in the days when all the power came from a spring. Also the same technology used today in Bose speakers.

http://www.gramophones.info/gramhmv163.html

How well this works will depend on how well they've manufactured the maths!

So, it's a horn for...a speaker (albeit the one that's built into the iPod)...that uses electricity.

This was an audio breakthrough in the days of the wind up gramophone, building the horn speaker into the box or cabinet - next thing they will be telling us how to lower the noise output by placing a scarf or hankerchief in the opening.

It says coming soon on the Griffin web site, not available now

http://upload.wikimedia.org/wikipedia/commons/a/a0/EdisonPhonograph.jpg

Any chance of a review? Internal speaker is nothing to shout about, hard to imagine it's much better after passing through a gramophone horn.

Also: http://www.r-hansen.com/tech/gram.html

Please change it to say iPhone, this was infinitely more impressive when it was working with the iPod rather than the phone.

That's a pretty neat and innovative idea, and the price isn't astronomical like most other iPap accessories. Thumbs up tbh

This works in just the same way as the throat on a horn speaker, basically it just picks up the vibration of the player and increases its reactance area with the air, just like the soundbox or horn on an old wind up gramophone

Most unusual and quiet noises are...

This is basically a sound box, and so works the same way the open body of a guitar or violin functions. The iPhone makes the device resonate and so makes sure the maximum amount of energy is turned from speaker/iPhone casing vibration into sound waves.

The problem is that this is driven by the iPhone speaker, and so will use (esp at high volume) much more battery power than is needed to produce the small voltages used as a signal by powered speakers. It will probably also lack in bass volume, and will never be that loud, so the iPhone volume will need to be at max most of the time. Considering how short the iPhone battery life is, you'll only want to use it with the iPhone plugged into the mains... in which case you might as well use mains powered speakers.

I'd say this is a neat stocking-filler for the hard-to-buy-for iPhone owner, or is a fun gadget for technology show-offs (which fits in with iPhone owner demographic quite nicely). As a practical way of listening to your music, I'd suggest this isn't worth the money.

i.e. the cheap passive ones costing around a fiver and sounding bleedin' awful. Fair enough for the job in question, I suppose, but another nail in the coffin of audio quality delivered curtesy of the portable digital music player.

They were doing this in the 1920's with crystal sets and headphones in mixing-bowls (a very effective combo).

Is this really how far we've come in 80 years?

I've got one of those - it's called a metal bucket. Stick your iphone etc in there and listen. Sounds awful though

So it’s an impedance matching device, just like the very first gramophone horns. That’s presumably why there’s a gramophone displayed on that iPod. Not exactly magic, and will most likely leave Messrs Bell and Edison unmoved. It’s a very cheap and good looking folded horn. Let’s hope it also sounds ok.

a refined version of the horns that graced old style gramophones. I can't see either Bell or Edison being surprised. Odds on one of them invented it and the other stole the idea.

But if they are selling, it must work at least to some extent, I'd think... Have to go hear it in person to see whether resonance alone can really do what they claim.

It's called a "megaphone".

Mine's the one with the word "Director" around the back.

Does it actually work???

So that would be what most people would recognise as a "horn" then - you know, like those trumpet shaped speakers used at outdoor event for the PA. All they've done is coil one up and make it look pretty.

It's wrong to say it amplifies the sound, it doesn't. It simply makes the process of converting the original movement of the speaker cone into sound much more efficient.

"So that would be what most people would recognise as a "horn" then - you know, like those trumpet shaped speakers used at outdoor event for the PA. All they've done is coil one up and make it look pretty."

It's more like a folded horn. Straight horn flares usually have a compression driver fitted to them whereas a folded horn will have a regular driver in them.

The thing nobody ever told me about exponential horns was, whether it was the radius or the cross-sectional area that was supposed to vary exponentially with distance .....

Yes it's just impedance matching. No it doesn't use resonance as resonance only boots narrow frequency ranges and that would sound horrible.

However even though this does not actually amplify anything, it causes the power output of the loudspeakers to rise.

Essentially it's like this:

Air is fairly simple to move under normal circumstances, however the membrane is much harder to move than the surrounding air. So the loudspeaker puts most of it's force into moving the membrane. It could push or pull a lot harder. Now the horn makes the air appear more stiff on one side and distributes that force to a larger area.

The major problem with horns is that the lowest frequency 3db point is a function of the area of the horn mouth and the length. It is 40 years since I did the calculations, but I seem to remember that to get down to 20Hz (the recognised limit of human hearing) you needed a horn 40 feet long and 20 feet in diameter at the mouth.

A little plastic box won't hack it for bass notes.