[Fpga-synth] Digital Waveguide Samples

[Eric Brombaugh]

Scott Gravenhorst wrote:
> Hello all,
> 
> I've posted three MP3 files made using my digital waveguide experiment.  I
> chose to use the system with the nonlinearity enabled because it was more
> interesting that way.  Each file consists of multiple excitations while
> slowly increasing the filter bandwidth starting at zero.  When the sample
> first starts, you hear clicks because the filter squelches the system so
> quickly there is no resonation.  As I increased the filter bandwidth, the
> system takes on a more musical character morphing from a tonal drum through
> a metallic sound.
> 
> http://www.fpga.synth.net/pmwiki/pmwiki.php?n=FPGASynth.DigitalWaveguide

Pretty cool!

I really like how the random phasing of the excitation pulse and 
existing signal interact to give a different sound for every pluck. An 
excellent model of a stringed instrument.

It's been a long time since I read anything about these sorts of PM 
sound generators, so I'm not up to speed on the current tech. However, I 
notice that you're just using a rectangular pulse for stimulus. Have you 
considered:

* Lookup tables of different shaped stimulus - could simulate 
hammers/plectra with different shape & stiffness.

* PRN generator with variable amplitude - broadband noise could drive 
the waveguide sort of like an organ pipe.

* Variable frequency pulse generator - might sound sort of like a bowed 
string, depending of the pulse shape. I think a bowed string would have 
some feedback to the bow though, so the stimulus tends to be tuned to 
the resonant frequency which would be a bit harder to simulate.

So many things to think about here...

Eric