I have created a new blog called MicIRP, which is a contraction of The Microphone Impulse-Response Project.
MicIRP will run in parallel to the Xaudia microphone blog, and aims to share impulse-response (IR) data from the many interesting old mics from our own collection and that come in for repair
The IR files can be used with convolution reverb programmes or plug-ins such as TL Space or Waves IR1 to simulate the sonic characteristics of the microphones. So they can be considered as filters or tiny spaces to modify your sound.
I have uploaded files for about 35 microphone to get things started, and will be adding many more mics as and when the opportunity arises.
And it is all completely free so have fun!