[sdiy] saw to tri/sine options

[David G. Dixon]

For the "new wave" we seem to have uncovered here yesterday, I have a
serious proposal for a name.  I preface this by reminding you that sharp
edges on a scope are barely visible if at all.  Hence, saw waves are really
slanted lines, and pulse waves are horizontal bars.

In this spirit, I suggest this new wave be called a "sigmoid" wave, since
that is in fact that the curve you would see on the scope is called.  It's
not as much fun as Frankensine or whatever, I admit, but it is accurate.

> -----Original Message-----
> From: synth-diy-bounces at dropmix.xs4all.nl [mailto:synth-diy-
> bounces at dropmix.xs4all.nl] On Behalf Of Kyle Stephens
> Sent: Tuesday, June 02, 2009 11:57 AM
> To: synth-diy at dropmix.xs4all.nl
> Subject: Re: [sdiy] saw to tri/sine options
> 
> 
> My, seems I've kinda discovered a monster? Stephensine as Jerry put it
> (good one!) or Tim's Sawn wave, either way ;)
> 
> The most powerful simulation tool in my arsenal right now is Microsoft
> Excel, which I know pretty well and otherwise use for most of my number
> crunching, but I wasn't sure how to express a tri wave in there though,
> and even less so the waveshaper transfer function, so very cool and my
> thanks to those who had the tools and know how to let us know the math
> behind it and hear what it would sound like (thanks Ian, David, Aaron, JH
> and Jerry!)
> 
> As for Dan, Aaron proposed the effect of running an 'incorrect' wave into
> the 'shaper might be Tube Screamerish - weird waves to be sure. Maybe try
> the TH VCO-1 waveshaper as mentioned earlier in this thread...
> 
> Waveshaper:
> http://mypeoplepc.com/members/scottnoanh/sitebuildercontent/sitebuilderfil
> es/vco1_schem2.pdf
> 
> >From here:
> http://mypeoplepc.com/members/scottnoanh/birthofasynth/id33.html
> 
> 
> ...with some pots instead of just trimmers (like the gain pot idea Mark
> mentioned), see what happens when you mess with the symmetry and the input
> level? I think Germanium transistors would be tricky but might give you an
> interesting sound if you can get a hold of a pair, a la a Fuzz Face or
> Zvex Fuzz Factory (though that might open a whole can of worms/mojo-voodoo
> debate when it comes to finding the 'right', if there is such a thing,
> beta values for the Germanium transistors). I wana give it a try on the
> breadboard today.
> 
> 
> Another question though: do you get a peak-ish wave when you run a sine
> into the same sine waveshaper? Sin^2(x)?
> 
> 
> _Kyle
> 
> --- On Tue, 6/2/09, mark verbos <mverbos at earthlink.net> wrote:
> 
> > From: mark verbos <mverbos at earthlink.net>
> > Subject: Re: [sdiy] saw to tri/sine options
> > To: "David G. Dixon" <dixon at interchange.ubc.ca>
> > Cc: "'Synth DIY'" <synth-diy at dropmix.xs4all.nl>
> > Date: Tuesday, June 2, 2009, 10:45 AM
> > add a gain control on the input while
> > you
> > re at it
> >
> > Mark
> >
> >
> >
> > On Jun 2, 2009, at 2:21 AM, David G. Dixon wrote:
> >
> > > Now I'm thinking I'll have to add a switch to my
> > oscillator to route
> > > the saw
> > > through the sine shaper.  This effect cannot be
> > obtained by filtering.
> > >
> > >> On Jun 2, 2009, at 12:10 AM, David G. Dixon
> > wrote:
> > >>
> > >>> For saw input, the result is a saw with a
> > sigmoidal (i.e., S-shaped)
> > >>> downslope rather than a straight one.
> > It's basically the downward
> > >>> sloping
> > >>> half of a sine wave, which stands to
> > reason.  I would bet that this
> > >>> waveform
> > >>> sounds rather pleasant.  I'll have to
> > give it a try.
> > >>
> > >> You could try running anything through it. I
> > imagine the effect would
> > >> be much like a Tube Screamer.
> > >>
> > >> - Aaron
> > >
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> 
> 
> 
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