Order Estimation

Given a desired frequency response, a rough digital filter order estimate can be obtained as follows:

• FIR: Look at the IFFT duration (e.g., $20\log(\vert h(n)\vert)$ )
• IIR: Start with half of the FIR order (equal degrees of freedom)
• In either case, convert desired frequency response to minimum phase whenever possible: Matlab code: http://ccrma.stanford.edu/~jos/filters/Matlab_listing_mps_m.html
• For piano strings, a low-order minimum-phase damping filter is fine because we're going to need a high-order allpass dispersion filter anyway