Resonant body, poly or mono?

gentleclockdivider
gentleclockdivider Member Posts: 212 Helper
edited October 2 in Reaktor

I am making a basic karplus strong instrument .
Three delay lines for the strings ( poly ) and 6 parallel comb filters for the resonant body .
I am deciding if the resoant body should be set to poly or rather mono as an effect .

Mono

image.png

Or poly ?

image.png

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Comments

  • Big Gnome
    Big Gnome Member Posts: 37 Helper

    It seems to me intuitively it ought to be mono since most (electro-)acoustic stringed instruments have a bridge that couples the strings together which in turn causes the soundboard to resonate; and that sort of inter-string crosstalk is a big component of those instruments' sound. I think making the resonator polyphonic, apart from the additional CPU overhead, would behave more like a bunch of monochords. But, hey, see what you like better and follow your muse.

  • ANDREW221231
    ANDREW221231 Member Posts: 349 Pro

    since body models are considered to be a linear time-invariant system it shouldn't really matter (unless maybe you are using feedback for coupling, in which case as Big Gnome said i would go mono)

    it is also possible to forego the body model by filtering the noise excitation instead as i believe as a LTI system they are equivalent

  • Chet Singer
    Chet Singer Member Posts: 73 Advisor

    If you're emulating an acoustic instrument, then modeling the body resonances with a single monophonic circuit is all that's required.

    Colin has a zero-latency convolution machine somewhere in the UL. You can load impulses into it from actual instruments and run your KS tones through them. I used an early version of it in Serenade, creating wooden body resonances from real instruments. It's a lot of fun.

  • Studiowaves
    Studiowaves Member Posts: 640 Advisor

    Sounds cool, mono resonance will work unless you want to mimic a pair of stereo mics.

  • gentleclockdivider
    gentleclockdivider Member Posts: 212 Helper

    Here's the ensemble , it's pretty simple and nothing spectacular
    The body can be set to poly or mono , just place it before the voice combiner when poly

    stringie.ens

  • Studiowaves
    Studiowaves Member Posts: 640 Advisor

    I like it, definitely on to something. I looked that up and it seems the theory dates back 30 or 40 years. What possessed you to try it.

  • gentleclockdivider
    gentleclockdivider Member Posts: 212 Helper
    edited October 12

    Well the resonant body (comb filters ) was something that the developer of Alpha forever showcased , and I thought why not give it a try in reaktor .
    It does make sense since these are just verry dense reflections
    The karplus strong part (strings ) is really simple , just a tuned delay line with a gentle lowpass in the feedback loop for damping (3 n this icase ) , coupling is feeding one string into the other , altough I am sure it's far more advanced then my simple implementation but it does the job

  • Studiowaves
    Studiowaves Member Posts: 640 Advisor
    https://community.native-instruments.com/discussion/comment/183839#Comment_183839

    It's natural sounding to me. Probably because it's a decent fundamental model of the way instruments naturally interact. Acoustic instruments like the string family naturally act like this. The string resonate loudly on some notes and dampen on others. The feedback is simply acting like the wood vibrates. The wood cross couples vibrations into the other strings and sets them in motion. It's known as sympathetic resonance, something I learned about tuning piano's. Well, ok, just chatting. Talk later

  • gentleclockdivider
    gentleclockdivider Member Posts: 212 Helper
    edited October 13

    I duplicated the resonator for true stereo , small adjustments to the gain coefficients of the comb filters(for both resoantor banks) has a huge effect .
    Me like

    stringie.ens

  • Studiowaves
    Studiowaves Member Posts: 640 Advisor
    edited October 15

    Uh huh, ambience in a way, isn't it. I had a chance to listen to it in the studio and it's definitely got potential. One instrument I can think of is the steel drum. I was tinkering around with it and it started to get close. I guess the feedback resembles the cavity of the drum somehow. Whatever, I like it and think it's really cool that someone did something that's not subtractive synthesis. Let us know when you get a good handle on it, as it stands it's probably well suited for short percussive attacks to set off a good sampled instrument. These kinds of things don't have layers like samplers and are the perfect companion to make samplers sound like they do have many many layers. I think you should make adjustment to the feedback system based on the midi note. That's like tuning the body to resonate the same on every note. That's not easily done with any instrument. Although too much perfection takes away the character of the instrument and they end up with a flat monotonous sound. I have a pretty nice semi hollow body guitar that has a dead spot on one of it's notes. I sure wish I could fix that but how….

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