sequence to perform filtering? which filter first? Hi all Is there a generally accepted rule as to which order to perform filtering in? 

for example if I have three iir filters, a low pass filter a notch and a high pass filter, which sequence would it be best to perform these in? or does it not make any difference at all? 

cheers, Graham.
Theoretically (with infinite precision arithmetic) order of LTI filters does not matter. If any of the filters is not LTI then order will be important. 

Plus, for finite precision arithmetic one should also take care of numerical error build up and potential instability issues especially with IIR filters where pole locations may become critical