Anyways I have been trying to implement 4 one-poll, all-pass filters in line. I guess to try and create a phaser effect. Here's what I have...
I have no idea if this is even close but it seems to break over 440 for the freq parameter. My math skills are very very lame so feed me gentle MSP fruit. Also just looking for pointers and not a full blown implementation as I like to work this stuff out a bit/puzzle through and see where I get and what I learn.
EDIT: I think I meant First order All Pass