Thanks for your reply! Seems like the coefficients are put up correctly, I am however experiencing another issue regarding this you might be able to assist with: https://forum.pdpatchrepo.info/topic/10730/creating-a-bandpass-filter-using-biquad

Thanks for your reply!

Good to know it's not only happening on my machine! Thanks for your assist, hopefully someone with knowledge about biquad~ comes along!

That simplified the math very well, even found a little error in the math, but fixed it now. I am however experiencing an odd error, if I load a song and start playing it, it only plays on certain gain levels, plus it only seems as if it's playing on every 2nd tick of the bandwith and center frequency slider. I find this behaviour odd, as I at current points is pretty sure the math is correct, so maybe it's a PD thing I missed? Just wanted to check in, if there's something you might know regarding this.
You can test it for yourself with the fixed math:
eq.pd

@weightless Seemed to solve my trigger problem! Great answer, and nice organising, opened my eyes a bit for what you can do. Now I just need to get the actual band-pass filter working. In case that's also something you're familiar with, I've made another post regarding this specifically: http://forum.pdpatchrepo.info/topic/10730/creating-a-bandpass-filter-using-biquad

Thanks for the help!

EQ_bandpass.pd

I've been trying to create a bandpass filter using the biquad~ object, and so far set it up as in the attached file. It's setup using following logic:

G, w0 and deltaw are adjustable, as the project shows.

As it is now, when I insert a sound file I'm able to change a bit on the sliders, but the sound completely disappear on certain settings, doesn't change in an expected manner, and the range of gain in which sound can be heard changes dependant on the other sliders(I should be able to simply adjust the filter's gain between -10 and 10 dB). I've gone through the math several times, and can't seem to find any errors, at least not if pd works the way I expect it to. Maybe there's an element that went over my head?

Any suggestions regarding this are highly appreciated, it's driving me nuts!

And a quick disclaimer: If you've seen a couple of posts similar to this one, they are other questions centered around the same project. I like to keep questions separate, even if they're for the same project.

Alright, so I think I understand what you're saying, but how would one approach it with a more complex situation like the one I attached to this comment?
eq.pd

Let's say I want to make the function Global_BANG does automatic. I tried doing something along what you've said, attaching the bang element to pack while using f as output, but it didn't seem to change. My hunch is it's because there's so many operations between the sliders and the pack that also would need triggers, but I worry this would cause a huge mess. Maybe there is a simpler way I'm unaware of?

sliders.pd

I have what I think is a very simple question, but it might have a less simple solution. If I have a scenario as in the attached project (multiplying slider values), is there a way for me to make the output update even if it's the 2nd input slider I'm modifying? I understand pd's way of working, that the 1st input is working as 'bang', but is there a way to make both inputs work as such without doing it manually?

Of course! Worked like a charm, highly appreciated!

ParametricEQ.pd

This might be a very specific issue, but I've been trying to figure out the core of my issue, and I keep failing. I'm trying to create a band-pass filter using the 'biquad~' object given the logic below:

Given 'G', 'w0' and 'deltaw' are adjustable.

However, it seems like no signal is passing through the filter at all. I should disclaim I'm still rather new to PD, so there might be some obvious mistakes I fail to see.

Any suggestions would be greatly appreciated!