how to model a wire mesh?

How do I model the fine wire mesh on the covering of some earphones or speakers?

You might want to just texture it.
Where is the camera in the shot?
Is this an up close macro shot, or a far away shot?

it’s upclose.

You could model two wires, side by side, with opposite waves, then use the array modifier to make many of them. Duplicate this, and rotate it 90 degrees to make the cross wires. Adjust everything to make the waves fit over and under properly. Then, apply the arrays, and trim the resulting mesh to the correct size. It will be very high poly, but won’t fall apart close up.

Once it’s done, of course, you could use it to burn a normal map for a lower poly microphone or speaker.

Thanks for the help… but what are normal maps?

Normal maps are images that are mapped to an object, which instead of providing colour information give information about bumps in the surface should be. Normal maps are useful for adding small details, such as scratches or indents, to a surface without having to include extra geometry.

More info in the manual,

Put simply, what Orinoco proposed was you use the high-poly mesh er… mesh, to bake into a normal map. This can then be applied to a mesh with a lot fewer polygons (for instance, a filled circle) and even at reasonably close distances the circle will appear to look like it has a mesh. However, normal maps do affect the shading, but they don’t create physical bumps… so if you go too close you will be able to see its a flat surface.