Not sure if you got that this new icon set actually changes the image to be more legible at different sizes by showing different amounts of detail. The big microphone has more dots on it than the little one.

The point is that the icons come in 3 sizes, so a small icon has less details, then a large one, this is a feature missing in the most icons sets: http://blog.useiconic.com/designing-iconic-across-different-...