General 2-nd order filter structure

Hello,

I'm trying to make a filter from scratch.
The formula is:
out(t)=a0*in(t)+a1*in(t-1)+a2*in(t-2)+b1*out(t-1)+b2*out(t-2)

Something went wrong.
I asked for help with the way I get a0, a1, a2, b1, b2 values on some scientific forum.

The question is about Core structure in general. Is it ok?

(calculations inside macros involve only f, r and SR values)

 

looks fine at a glance... the merge module at the end seems pointless though?

i have a bunch of tutorials on filter design on the website in my signature, one of them contains an ensemble for testing the frequency response of a filter, if you need something like that...

 

Dude, such a massive stock of good tutorials! Thank you for sharing.

There is a good dsp filter modeller online: http://www.micromodeler.com/dsp/
I built 2-nd order filter there and it gave me the all the values and structure:

The scheme look like mine one. Then I just copied values to my core structure...:

...connected it to white noise source and got this:

It's definitely not the LPF designed on first screenshot.
Could anybody point out what is wrong?

 

the ensemble is here

 

hmm, maybe you are using your spectrum analyzer wrong? hooked it up to an EzFFT analyzer and got this frequency response:



btw those are some leet coefficients...

 

Yes, my analyzer was set the wrong way. Sorry for troubling you.
And huge thanks for filter tutorials on your site! Very good source of useful basic examples