Audio Plugin - AU/VST

Hi!

I'm very new to matlab.

I tried to develop an AU/VST plugin that process audio in real time and apply several type of filters, gain, polarity reverse, etc, with educational purposes.

I have some problems because some filters that matlab implement, need to receive constant variables as filter inputs.

With CROVOVERFILTER function i implemented LR filter, with BUTTER function now its possible to work with no constant inputs, but for eliptic and chebyshev filters this is not possible.

Any solutions??

Another question is related with APF 1st and 2nd orders. How can apply this filter in real time? I want to pass FREQUENCY, ORDER and Q to APF and implement it.

I found a function that calculates coefficients but I can't apply APF to y object that correspond to process (obj, x).

Thanks a lot