Plucked String

[Tim Kleinert]

Here's an elaborate plucked string model. The controls are pretty self-explanatory.

plucking: transient shape, force, stiffness, position
string: tuning, loss, absorption, harmonics
damper (on key release): speed (with optional release velocity sensitivity, yes sir ), stiffness, HF and LF damping

The nice thing is that many of these parameters should be controlled by keyboard tracking and/or velocity. And here's where the G2 shines: just hit those morph buttons and tweak away!

I used comb filters instead of log-tracking delays. The extra DSP usage doesn't matter, because I would hit the memory headroom otherwise anyway. And the bonus is: zero tuning issues . A voice uses half a DSP, both in cycles and in memory, so that's 15 voices from an expanded G2, or 7 from an unexpanded one.

There are some nice tricks in there, like filling the delay line with exactly one cycle of the excitation signal, and using delays as allpass filters to induce spectral dispersion on the strings (the "harmonx" parameters). The benefit compared to using "real" allpass filters is that the tuning remains constant (...mostly ). There are some nice inharmonic dispersions you cannot get with this, but as the G2 lacks real allpass filters anyway, it's the only solution. (Robs allpass filter and the MultiFilter allpass mode both have unity gain issues )

All variations filled, and optimised for keyboard performance (which is where the joy of physical modelling lies anyway .)

Enjoy.

best,
tim

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PluckedString TK.pch2
Description:	elaborate plucked string physical model	Download
Filename:	PluckedString TK.pch2
Filesize:	3.86 KB
Downloaded:	2702 Time(s)

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[cebec]

nice job, tim!!!

also, isn't the 6 dB BP output of the 'Filter Multi-mode' a real allpass?

[Tim Kleinert]

[Chet]

Thanks for posting this. I'm gonna have to take a look at that allpass filter; it sounds really good, and like you said, doesn't mess up the gain. I was able to make a neat-sounding marimba with only a couple of knob twists.

[jamos]

This is amazing, Tim. Good polyphony, too - thanks!

[mosc]

Excellent. Thanks, Tim...

[Chet]

[mosc]

[Chet]

Thanks, Howard. I tried it out and it does what Tim described, although the gain was sometimes appeared a little more than unity. But it's definitely much better-behaved than the Clavia-supplied allpass filter.

I can easily get some neat ethnic sounds out of it. But like Tim said, it tends to skew the tuning of fundamental pitch, so some compensation is necessary.

Thanks again.

[seanwayland]

Hi tim ,
excellent werk . Is it possible to set a velocity threshold somehow. Below the threshold keystrokes just "detune" the patch , above the threshold it " replucks" the string . That way you could possibly control playing legato and staccato . Another option would be for it to work like a hammond organ and "detect" legato playing ( when a key is pressed while another key is still down ) . I will work on this . It would work only work in mono I guess ...
cheers
sean

[kara]

This sounds excelent !
It's way above my knowledge of programming the G2X, so thank you very much for sharing this.

k

[seanwayland]

hi tim ,
Hope all is well. I have been experimenting with your guitar patch . I put an ADSR at the end to make it legato . At this point if a key is held down the next note pressed plays staccato without the ADSR. Is there a way to reverse this which would make more sense from an articulation point of view . I want to be able to play legato or staccato with lines ... please email me seanwayland@gmail.com thanks
best regards
sean

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wheel att guitar.prf2
Description:		Download
Filename:	wheel att guitar.prf2
Filesize:	9.82 KB
Downloaded:	1398 Time(s)

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[Tim Kleinert]

I emailed you.