[sdiy] dsPIC Stuff

[Scott Gravenhorst]

blacet at blacet.com wrote:
>Nice sounding tracks and interesting project!
>
>So there are just two pot controls for the whole synth? What range of
>sounds do they provide?

The pots control the reflection filter's Fc and linear damping.  The range of
sounds is fairly wide from drum-like to plinky to gut string to metallic.  The Fc
pot controls the rate at which higher harmonics are diminished while the linear
damping pot controls frequency independent attenuation.  Since the Fc pot's action
can cause a reduction in sustain as Fc is decreased, the damping pot can be used
to restore sustain length.  Likewise when Fc is raised, sustain can become very
long and linear damping can be used to reduce it.

http://electro-music.com/forum/download.php?id=32533 is a sample using only one 4
string engine where I had a simple test MIDI sequence running and I was slowly
twizzling the two pots.  This sample came from a somewhat earlier development
stage so there are some differences and warts: Only 2x oversampling was applied,
so the instrument's range is an octave lower.  I also used only one tuning table
where the current version uses 64 tuning tables one of which is selected by the Fc
pot.  This helps to mitigate the effect of the reflection filter being a first
order LaGrange interpolator which gives a fractional delay effect and causes
noticable detuning of the higher notes as Fc is decreased.  Also, there may be
some clipping in the sample due to a rather hot output buffer amplifier.

-- ScottG
________________________________________________________________________
-- Scott Gravenhorst
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