Hi, I am starting on the examples in Andy Farnell's "Designing Sound" but I am also trying to translate the patches into Max as I go. I am wondering if anyone on this list might know which Max objects will work best to replace [bp~] and [hip~]. I am currently replacing [bp~] with [reson~] and I'm replacing [hip~] with the right outlet of [cross~]. However, I am getting slightly different results than Farnell's examples. At the moment I'm dealing specifically with the "phonetones" examples and even more specifically with the contents of the "tline" subpatcher.

Hoping someone can offer a little advice. Thanks.

Is the Biquad Filter with a Filtergraph too much.

[biquad~] and [filtergraph~] using the bandpass option might be okay. Take a look at [onepole~] as an alternative to [lop~] and [hip~].

Thanks for the replies. I ended up discovering that the discrepancy in sound was really originating with [bp~] and [reson~]. These two filters just don't sound the same and I've tried different Q settings between the two and just can't get them to sound the same.

If anyone around here uses Pd and Max 5 (and cares) I've attached two patches that show the difference in sound between the two.

http://www.pdpatchrepo.info/hurleur/filter_test.pd

Sorry, somehow I didn't make the second post I intended. I've attached the Max 5 patch to compare to the Pd patch in my previous post.

http://www.pdpatchrepo.info/hurleur/filter_test.maxpat

Very different indeed. From Pd's source code (file d_filter.c) I understand it only implements feedback sections, not a feed-forward section as is drawn in [reson~]'s scheme. Therefore, the filtering is less extreme in [bp~].

If you want to make a filter in Max which is similar to [bp~], you could use Msp's [biquad~] with non-zero coefficients for the feedback sections (b1 and b2) and the gain (a0) only. But then you have to compute the coefficients yourself, from the frequency. Take a look at function sigbp_docoef(), starting at line 252 in d_filter.c from Pd's source code, to see how it is done. It may not be too difficult, if you know that x->x_sr means samplerate.

Katja