Make your teeny music player's speaker louder

In this Instructable we investigated ways to boost the output from any mobile phone's built-in speaker... without any electronics!

Step 1 How it works

The detail of the physics is beyond me, I'm sorry to say.
The basic idea is that loudspeakers don't transfer the electrical power supplied to them into sound very efficiently (about 1% see here http://en.wikipedia.org/wiki/Loudspeaker and here http://www.maplin.co.uk/Module.aspx?ModuleNo=3273#specifi for example).
One reason for this is that the cone doesn't 'couple' well to the air, because air is rather less dense than the material the speaker's made of.
As I understand it, it's like when you strike one of those practice golfballs made of foam, you give it a good punt, but it doesn't actually go that far... because the ball's so light you're unable to transfer much energy to the puny ball http://www.youtube.com/watch?v=wSlMupvTwOE.

Comments

[kctess5]

Think of it as an impedance matching transformer, the horn couples the low acoustic impedance of air with the high impedance of the driver, as you said, it makes the air harder for the speaker to move

[AustinMiniMan]

Cutting that could not have been fun.

[dudenitx]

[masterochicken]

5*. I quite enjoyed it.