I do not remember the values of all the components as I only saw the circuit for a brief moment in an interview but, as far as I can remember, the positive input was connected to a potential divider consisting of two equal value resistors to +Supply and -Supply.
The invering input was being fed from a mic pre-amp circuit which I believe was capacitively coupled and there was another resistor in series with the input.
CJT - Could you give me some pointers as to how I would go about an Op-Amp analysis as it has been some time since I have done one.
Thanks.