On Thu, 20 Sep 2007 15:57:07 +0100, "Keith G"
wrote:

Now, exposing yet more ignorance in public (as I am wont to do) - it is
fair to say that a dynamic mic works like a conventional speaker in
reverse and a 'condenser' mic works like an electrostatic speaker in
reverse...???


Zackly right. And in theory you can use either for either function.

The big difference between a mic and a speaker is the distance the
diaphragm is expected to move. Because of this, speakers tend to be
designed floppy. That means the main resonance is below the audible
range. Mics, on the other hand, can be stiff, so the resonance is
placed high by stretching the diaphragm. The exception in mics is the
ribbon, which uses a low resonance frequency like a speaker.

d

--
Pearce Consulting
http://www.pearce.uk.com