[PD] emulating an acoustic hi-hat pedal

[Kyle Klipowicz]

Someday I hope you make a big ole' physical modeled jazz drum kit, Andy.

Genius!

~Kyle

On Sat, Nov 29, 2008 at 10:31 AM, Andy Farnell
<padawan12 at obiwannabe.co.uk>wrote:

>
> Hey Patrick,
>
>
> It's the "everything in-between" bit that is hard. A hihat is one
> of those instruments that seems really simple, but on deeper analysis
> you see it is an amazingly complex and subtle device (which is obvious
> when you hear a really good drummer playing). With samples you can get
> the usual opening and closing strike sounds, and the cup/clash.
>
> But if you want a really good model you probably need to look at
> physical modelling and granular methods.
>
> The two parts can rattle against each other causing new excitations.
>
> Sometimes the top cymbal rotates around the bottom one, creating a
> rolling 'clatter'.
>
> The pressure of the pedal pushes them together harder increasing
> the frequencies (speeding up the roll - like if you push down
> in the middle of a rolling dinner plate) and damping both parts more.
>
> You can hit it on the edge or at any radius from the centre. As a simple
> rule the spectral complexity increases as you move outwards, hitting
> the bell in the middle produces a purer, shorter tone.
>
> You can use the tip of the stick, or brush, or hit lower down
> to get a less elastic impact with more energy transferrence (louder
> and noiser).
>
> So for the input vector; for pedal you probably want two continuous
> ranges, position and pressure (where they are touching), and for
> excitation you probably want two more impact event parameters,
> energy (0.5 * mass * velocity^2) and duration (impulse).
>
> You can also model leaving the stick connected, which damps the
> vibration at one point and reduces the modes.
>
> A full physical model of two interacting centre supported circular
> plates is certainly too expensive. FM methods can give you the
> raw spectra to blend according to interaction rules. (In fact -
> because the relationship of spectra in both FM and the disc modeal
> model both derive from Bessel functions you can get very natural
> evolution if you choose the right synth model - complex FM with
> multiple modulator sources works extremely well.)
>
> The trick is mapping the control params onto the synthesis params.
> As they come together you can tap off a little bit of the lowest
> and strongest vibrational mode (lop~ -> max~) and use it to
> make impulse spikes that amplitude modulate the other plate.
> Of course this is a reciprocal relationship (the lower plate
> also rattles against the upper one) - so it's ring modulation
> of the two maximum excusions to get a 'rattle modulator'.
> Moving the lop~ up and bringing the clip down will create the
> impression of the plates being forced together.
>
> The other approach is to make a parametric map from samples
> into a great big wavetable to use as grains. I have never
> tried it but I think that would work well for hi-hat.
>
> a.
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> On Wed, 26 Nov 2008 01:27:23 -0500
> patrick <puredata at 11h11.com> wrote:
>
> > hi,
> >
> > would it be possible to patch an acoustic hi-hat pedal complete with
> > heel-splash sound, closed sound, open sound, and everything in-between.
> >
> > i am not so sure where to start, i want a sampler-base solution.
> >
> > adsr, playing with filters, morphing of sounds, using 2 samples or more
> > (open, middle, close, very close). i would gladly pay a beer for this.
> >
> > pat
> >
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>
> --
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>
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