# Suggest a geometry for headphone's speaker system

• mirreb9
In summary, the question is asking for a suggested geometry to assemble a speaker that works using magnetism. The speaker would use a varying voltage applied across a coil attached to a diaphragm in the field of a permanent magnet to create a force that moves the coil. The speaker would also have access to a signal, short coil, rod-shaped permanent magnet, and diaphragm. The motivation for the suggested geometry is to improve energy transfer compared to the commercial design. The poster is having difficulty with the motivation portion and has provided a drawing of their proposed geometry. They have been asked to show their attempt to solve the problem before receiving any further guidance.f

#### mirreb9

Summary:: Suggest a geometry

Hello! I have difficulties with this question. It is translated from Swedish so if something's weird tell me.

The speakers in headphones often work with the help of magnetism, when a varying voltage is applied across a coil attached to the speaker membrane. The coil is in the field from a permanent magnet, so the current through the coil will create a force on the coil so that it moves. You have access to signal, short coil, rod-shaped permanent magnet and diaphragm. Suggest a geometry that can accomplish this. Motivate your answer.

I have mostly difficulties with the motivation part, i think i have made the right drawing.

(This is not the geometry used commercially. It has a different shape of the permanent magnet for more efficient energy transfer.)

Last edited:
The translation isn't fluent.
Their saying, given an input signal, a short coil of wire, a rod-shaped permanent magnet, and a diaphragm, show how to assemble these parts and describe how it would work.

That said, this is a homework problem - so you need to show us your attempt to solve it before you get any direction from us.

See the homework guidelines here:
Guidelines

mirreb9
The translation isn't fluent.
Their saying, given an input signal, a short coil of wire, a rod-shaped permanent magnet, and a diaphragm, show how to assemble these parts and describe how it would work.

That said, this is a homework problem - so you need to show us your attempt to solve it before you get any direction from us.

See the homework guidelines here:
Guidelines

Thank you! I will look at the guidelines.

Welcome to the PF. I have moved your thread to the schoolwork forums for you.
Summary:: Suggest a geometry

Hello! I have difficulties with this question. It is translated from Swedish so if something's weird tell me.

The speakers in headphones often work with the help of magnetism, when a varying voltage is applied across a coil attached to the speaker membrane. The coil is in the field from a permanent magnet, so the current through the coil will create a force on the coil so that it moves. You have access to signal, short coil, rod-shaped permanent magnet and diaphragm. Suggest a geometry that can accomplish this. Motivate your answer.

I have mostly difficulties with the motivation part, i think i have made the right drawing.

(This is not the geometry used commercially. It has a different shape of the permanent magnet for more efficient energy transfer.)