Hi Julián,
I would (and did) use faust2octave for that.
Cheers,
Julius
On Mon, May 31, 2021 at 7:13 PM Julián Villegas <jul...@u-aizu.ac.jp> wrote:
> Hi,
>
> How can I inspect the value of a variable in Faust? I’m trying to build a
> spectral tilt filter in Matlab (for learning purposes), following the Faust
> implementation. The results are wrong in Matlab, and I would like to
> compare my variables in Matlab with those in Faust.
>
> This is what I have so far in Faust:
>
> import("filters.lib");
> import("noises.lib");
>
> alpha = hslider("[1] Slope of Spectral Tilt across
> Band",-1/2,-1,1,0.001);
> f0 = hslider("[2] Band Start Frequency [unit:Hz]",100,20,10000,1);
> bw = hslider("[3] Band Width [unit:Hz]",5000,100,10000,1);
>
> process(x) = no.noise : spectral_tilt(2,f0,bw,alpha) : _;
>
> and this what I have in Matlab:
>
> function tilt()
>
> sr = 48000;
> N = 10; % Number of poles
> alpha = -0.5;
> f0 = 100;
> f1 = 18000;
>
> noise = rand(sr,1);
>
> w0 = 2 * pi * f0;
> r = (f1/f0)^(1.0/(N-1));
>
> mp = w0*r .^ (0:N-1);
> mz = w0*r .^(-alpha + (0:N-1));
>
>
> % prewarping for bilinear transform
> mph = prewarp(mp,sr,w0);
> mzh = prewarp(mz,sr,w0);
>
> for i=1:N
> g = mph(i)/mzh(i); % a0/b0
> [b1, b0, a1] = tf1s(1,mzh(i),mph(i),1,sr);
> noise = g*filter([b0, b1],[1, -a1], noise,sr);
> % soundsc(noise,sr);
> end
> plot(noise)
> soundsc(filter(Ba,[1 Aa],rand(sr,1)), sr)
>
> end
>
> function warped = prewarp(w,sr,wp)
> T = 1/sr;
> warped = wp * tan(w*T/2)/tan(wp*T/2);
> end
>
> function [b1d, b0d, a1d] = tf1s(b1,b0,a0,w1,sr)
> c = 1/tan(w1*0.5/sr); % bilinear-transform scale-factor
> d = a0 + c;
> b1d = (b0 - b1*c) / d;
> b0d = (b0 + b1*c) / d;
> a1d = (a0 - c) / d;
> end
>
> I’d like to compare the Matlab results in mzh, and mph, with those of
> Faust (e.g., a0,b0, etc.), but I can’t figure out how.
>
> I’m sorry if this is obvious, I’m new to Faust.
>
> Thanks,
>
> Julian Villegas, Ph.D.
>
>
> PS: The Matlab code is based on that provided in "Closed Form Fractional
> Integration and Differentiation via Real Exponentially Spaced Pole-Zero
> Pairs” by
> Julius Orion Smith and Harrison Freeman Smith.
>
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--
"Anybody who knows all about nothing knows everything" -- Leonard Susskind
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