earlevel wrote:The Behringer Model D apparently implements the highpass option this way. I've seen people confused as to why it doesn't sound like a highpass, which it won't if they have Emphasis (resonance) turned up. The lowpass ladder has no phase shift in the passband, -180 degrees at the corner, feedback is negative. So yes, it works fine, but feedback won't work as user would expect, because it adds the lows back in and you end up with more of a peaking filter.
Thanks! Yes, that's my problem too (one of them, actually), low frequencies are still very much audible.
For now I'd say that my LP multimode "moronic solution" mentioned earlier sounds better to my taste than the current one
aciddose wrote:To get a true high-pass you'd need to input the signal between the capacitors. So in electronics terms you'd replace each 1n cap with two caps.
Now the problem is that ...
Thanks! I wish I could understand it on a detailed level. I've read a couple of massive discussions on filters that you, Vadim and other experienced guys had participated in here on KVR, and as a result I understand that I need to have a good electronic circuit knowledge in order to do some of the less trivial stuff mindfully.
(If you didn't want the input-(inverted)-pole-mixing capability you could just input the signal to the first stage capacitor pair for a 24 dB high-pass, or the third stage for 12 dB high-pass
Sorry, I don't quite get it. Do you mean feeding the input right to the first trapezoidal integrator?
(If you're going to all the expense anyway you might as well do the pole-mixing and open up numerous other more useful modes.)
The feedback path would then work correctly!
If you mean using only LPs, then I did it, but perhaps something's wrong with my calculations for HP and BP modes. I still can't find the mistake in algebra though unfortunately. Both HP and BP modes don't have an acceptable attenuation, that's why I'm doing the HP design.
I'm not certain that even one accurate discrete differential model exists in software anywhere.
Both of your and Earlevel's answers and a brief mentioning of the differentiator-based filters in the book makes me feel a bit stunned
Firstly I wonder what would be the right implementation of a differentiator for VA filters (this is interesting by itself aside from the ladder), and secondly will it even be of any use in this task except for getting some practice.