[sdiy] Resonator type filters

[rsdio at audiobanshee.com]

Your statement begs the question: What is a "straight standard FB"?

I assume you mean Filter Bank, but how many frequencies are there? How far apart are they spaced? What is the relationship between the frequencies - linear, logarithmic? If you have answers to all of these questions, then you can adjust the Virta user interface controls to model the straight standard filter bank. You can also experiment with variations that would be difficult in a pure analog FB.

One feature in Virta that I think is really cool is that you can force the filter frequencies to fall on selected notes in a scale. So, after defining the broad parameters for frequency spread and count, the software will move the various frequencies around to fall on the closest notes in the scale that you define, rather than having one strict mathematical formula that they all must follow. But you don't have to use this feature if the straight standard filter bank doesn't space its frequencies in that manner.

Brian


On Jun 30, 2017, at 4:32 AM, Ian Fritz wrote:
> Ah ha!  Many thanks, Brian. I read through the manual and don't see anything about a straight standard FB. Do you just feed the source material into both of the vocoder inputs or something?  I'll definitely download it and see what I can figure out.
> 
> On 6/30/2017 2:51 AM, rsdio at audiobanshee.com wrote:
>> One place you might look, Ian, is Madrona Labs. The Virta plugin is a VST/AU for OS X and Windows that offers a resonant filter bank among other complementary effects.
>> The Formant section is where the action is. You can dial in classic, analog-style filter banks from 8 to 32 bands, or even an 256-band FFT mode. The spacing of the classic frequency bands can be shifted, stretched, or compressed in various ways. The other combined effects, like MIDI-controlled pitch shifting, help process the incoming audio to get it into shape for the format filter section. You might have to look around for some demos.
>> http://madronalabs.com/products/virta
>> I'm having a little trouble launching my DAW due to other plugin trial versions that have expired and are causing a crash. If not for that, I would look through the Virta presets to see if there are any string synth filter setups that would help get you started. There is a thread on the Madrona Labs Software forum for Virta presets that might be a help.
>> Brian Willoughby
>> p.s. In the tradition of full disclosure, I should probably make it known that I am affiliated with Madrona Labs. I do the hardware design, firmware development, and USB protocol drivers for such products as the Soundplane and the imminent Euro rack module. I am not involved in the software plugins, but their sales do fund my hardware designs indirectly, so one could argue that I have a conflict of interest. That said, I did play around with the plugin for a while when it was first released and it seems very powerful - far more than I think can be thrown together with a ton of building blocks from any other sound processing product.
>> On Jun 29, 2017, at 11:11 AM, Ian Fritz wrote:
>>> Yes, but I have never never seen one with the high resonance and the large number of stages needed for a string filter -- do you have some specific examples?  I would love to have a VST string filter but cannot find any.