Circuit modelling ? How do you know ?

[zzz00m]

I dunno, maybe ask Urs?

[bmanic]

Even with IC's you can at least get an idea by measuring input vs output, right? Circuit modeling comes in all forms though.. you could say you modeled a capacitor and just write the most basic filter.

[Funkybot's Evil Twin]

What does modeling even mean? A model could be, "I approximated inputs and outputs based on measurements and made a model using traditional DSP." If that device was made with circuits, didn't I just model a circuit? Doesn't automatically mean it's a good or even accurate model. Could just be mimicking one setting and not even well. Doesn't not make it a model.

Don't get hung up on semantics or marketing. Demo gear. Check it out for yourself. Run tests. Use your ears. Buy what you like.

[Urs]

Regarding integrated circuits, for Repro we used the circuit diagrams shown in the patents filed for the respective VCO, VCF and envelope chips. Patents are long gone, the tech is available for anyone to use. Heck, some patents contains formulas which can be used 1:1 in code.

[resynthesis]

But integrated circuits?

And ICs with a big glob of black epoxy on them ?

Not sure but I imagine there are ways to get the Epoxy off

Indeed, some of the people on diystompboxes and freestompboxes are experts. That's why things like the Klon were reversed

[EvilDragon]

It's a bit more certain when the software maker actually has constructed hardware devices. For instance the 32C EQ circuit emulation in Harrison's Mixbus32C DAW is claimed to be an exact replica of every resistor, transistor and other component of the 32C EQ from the famous Harrison mixing console of the 70s (Michael Jackson, Supertramp, Zappa, ABBA, Paul Simon, etc...) and that claim has more weight since Harrison made the hardware in the first place.

Well, there's no saturation in 32C's EQ "circuit emulation". So I find it highly dubious that they did any actual circuit modeling.

https://www.admiralbumblebee.com/music/ ... er.html#eq

[Stefken]

Regarding integrated circuits, for Repro we used the circuit diagrams shown in the patents filed for the respective VCO, VCF and envelope chips. Patents are long gone, the tech is available for anyone to use. Heck, some patents contains formulas which can be used 1:1 in code.

Is there like a path one can go as a noob in this area to get a feel for it. I'd like to have a crack at trying to emulate a filter but I'm not a coder.
So if gets too nerdy in terms of math and code, it's not for me. But if there is an intermediate level with some abstraction going on and some graphically oriented tools that can help you with generating formulas, it might be a nice project.
I often wonder how modeling is done.

[resynthesis]

^
Have a look at this Reaktor video - it's a bit less math / code intensive than some (but it leads onto Vadim's book)

https://www.youtube.com/watch?time_cont ... pAxQIUGT4w

[Urs]

Regarding integrated circuits, for Repro we used the circuit diagrams shown in the patents filed for the respective VCO, VCF and envelope chips. Patents are long gone, the tech is available for anyone to use. Heck, some patents contains formulas which can be used 1:1 in code.

Is there like a path one can go as a noob in this area to get a feel for it. I'd like to have a crack at trying to emulate a filter but I'm not a coder.
So if gets too nerdy in terms of math and code, it's not for me. But if there is an intermediate level with some abstraction going on and some graphically oriented tools that can help you with generating formulas, it might be a nice project.
I often wonder how modeling is done.

The first issue is the understanding of the relation between current and voltage. Once you grasp that, the maths are excessively simple.

The second issue is the implementation of these simple formulas in an algorithm. Simple formulas, extremely difficult problem.

[chk071]

Does it really matter? I mean if the plugin sounds better than anything else you've ever heard that it's "supposed" to be modeling, who cares? If it sounds like crap, I won't buy it anymore. If it sounds great, I will buy it.

Isn't that all that really matters?

Yes.

[Stefken]

^
Have a look at this Reaktor video - it's a bit less math / code intensive than some (but it leads onto Vadim's book)

https://www.youtube.com/watch?time_cont ... pAxQIUGT4w

@resynthesis
Thanks for your answer. I realise that I asked for a graphical tool and Reaktor is an obvious answer.
Let me clarify more what I mean which a graphical tool.
I had a glace at mathlab and the story of the zeros, poles, and gain.
You can have graph representations and the numbers for a standard filter like e.g. a butterworth filter.

But I don't want to emulate a butterworth filter. How do you go about if you want to emulate a MS-20 filter for example. Are there tools where you can draw in graphs, or that can analyse audio and that will generate the numbers for you?

If this is a case of "you can't have your cake and eat it too" (it probably is) you can tell me so.
"If you're not willing to plunge in the deep and do the hard work, you can't get results." Fair enough.
But the math behind it, is pretty deep I guess.

Maybe what I need is a good documentary or a good book that shows the magic in an accessible way.
A documentary showing people measuring up equipment, digitally constructing the circuit diagrams and generating the functions and numbers for the dsp.
I thinks it is a thing of beauty when you see how people can digitally model an analogue device. It's just a pretty steep learning curve to understand it if you don't know where to start.

Make any sense?

[Stefken]

Regarding integrated circuits, for Repro we used the circuit diagrams shown in the patents filed for the respective VCO, VCF and envelope chips. Patents are long gone, the tech is available for anyone to use. Heck, some patents contains formulas which can be used 1:1 in code.

Is there like a path one can go as a noob in this area to get a feel for it. I'd like to have a crack at trying to emulate a filter but I'm not a coder.
So if gets too nerdy in terms of math and code, it's not for me. But if there is an intermediate level with some abstraction going on and some graphically oriented tools that can help you with generating formulas, it might be a nice project.
I often wonder how modeling is done.

The first issue is the understanding of the relation between current and voltage. Once you grasp that, the maths are excessively simple.

The second issue is the implementation of these simple formulas in an algorithm. Simple formulas, extremely difficult problem.

Thans Urs. Are there accessible starting points you can direct me to. I don't know where to start

[chk071]

I'd think starting with a virtual Modular like Reaktor, SynthEdit, or Flowstone would be a good starting point. And with those, and a good documentation, you can even go down to programming level.

[lfm]

amp modeled circuit with 1 dB gain
output signal dB= input signal dB + 1 dB
out=in+1

that's all it could mean.

Ask if descrete components are modelled and see how much mumbo jumbo you get as answer.

[Stefken]

I'd think starting with a virtual Modular like Reaktor, SynthEdit, or Flowstone would be a good starting point. And with those, and a good documentation, you can even go down to programming level.

I've glanced at Synthedit/Flowstone but I don't want to invest too much time in it as I don't see a future for it.
I've seen the dsp in Synthedit/Flowstone for your average, not so bad but also not so good, low pass filter.
There are also examples floating around on the web, but that's just copying some else's code.

But how do you go about to making a REALLY GOOD ms-20 filter; how do you make that repro filter.