[sdiy] Wave terrain synthesis (was Re: Generating acyclicwaveforms?)

Wed Mar 24 21:50:48 CET 2010

Didn't I explain the concept of "volts" to you just the other day?

http://search.retrosynth.com/synth-diy/search/lookit.cgi?-v1001.337

Honestly, I'd think it would be safer to assume that a poster here knows
volts from amps before assuming they know calculus at all.

On Wed, 24 Mar 2010 21:39:53 +0100
cheater cheater <cheater00 at gmail.com> wrote:

> On Wed, Mar 24, 2010 at 21:29, Jerry Gray-Eskue
> <jerryge at cableone.net> wrote:
> > A rather broad assumption considering that the only prerequisite
> > for this form is an interest in DIY Synths.
> > I am sure there are several people here that understood what you
> > stated, but I suspect that there are several more that are
> > interested in your comments, and if they were was a bit more
> > verbose English explanation of your concepts more of us would
> > benefit from your expertise.
> 
> I guess you're right. I can only invite everyone who reads this to
> pick up and read an introductory linear algebra/calculus book for
> technical university students that covers complex and linear algebra,
> discrete mathematics, classical calculus and multivariate calculus.
> This is infinitely useful in understanding sound synthesis, be it
> analog or digital.
> 
> Unfortunately the mathematics above can't be explained to the layman
> in less than ten paragraphs at which point it becomes pointless, but
> if you read the first paragraphs of definition for these terms you
> should be able to understand everything:
> 
> - parametrized curve
> - vector perpendicular to a curve
> - vector parallel to a curve
> - derivative of a vector
> 
> Cheers
> D.
> 
> P.S. in the previous post I should have said 'phase' not 'phasor' of
> course :-)
> 
> 
> >
> >
> >
> >
> > -----Original Message-----
> > From: cheater cheater [mailto:cheater00 at gmail.com]
> > Sent: Wednesday, March 24, 2010 2:22 PM
> > To: Jerry Gray-Eskue
> > Cc: synth-diy at dropmix.xs4all.nl
> > Subject: Re: [sdiy] Wave terrain synthesis (was Re: Generating
> > acyclicwaveforms?)
> >
> >
> > I assumed everyone here knew analytic geometry.
> >
> > D.
> >
> > On Wed, Mar 24, 2010 at 20:22, Jerry Gray-Eskue
> > <jerryge at cableone.net> wrote:
> >> And a little subspace distortion....;)
> >>
> >> -----Original Message-----
> >> From: synth-diy-bounces at dropmix.xs4all.nl
> >> [mailto:synth-diy-bounces at dropmix.xs4all.nl]On Behalf Of Tom
> >> Wiltshire Sent: Wednesday, March 24, 2010 1:45 PM
> >> To: cheater cheater
> >> Cc: synth-diy at dropmix.xs4all.nl
> >> Subject: Re: [sdiy] Wave terrain synthesis (was Re: Generating
> >> acyclicwaveforms?)
> >>
> >>
> >> Hehe, you *must* be making that up! Just add more dilithium
> >> crystals!
> >>
> >> T.
> >>
> >> On 24 Mar 2010, at 18:32, cheater cheater wrote:
> >>
> >>> Actually it's some sort of generalization of both at the same
> >>> time.
> >>>
> >>> If you have a trajectory C_1(phi) : [0, 1] -> R^2 over which the
> >>> terrain is scanned then translating it by a vector by doing
> >>> C_2(phi) = (C_{1,x}(phi) + L_x, C_{2,x}(phi) + L_y) (where L is a
> >>> certain vector and (x,y) signifies a vector in R^2) will work
> >>> just like a wavetable index scan in the part of the trajectory
> >>> that is perpendicular to the vector L, and will work like pitch
> >>> bending in the part of the trajectory that is parallel to the
> >>> vector if dL/dt is a non-zero constant.
> >>>
> >>> Changing the function C_1(phi) or the phasor function from phi(x)
> >>> = x to something different will work like PM.
> >>>
> >>> D.
> >>>
> >>> On Wed, Mar 24, 2010 at 11:23, Tom Wiltshire
> >>> <tom at electricdruid.net> wrote:
> >>>> I find it very interesting that this technique makes similar
> >>>> sounds to FM,
> >>>> since in my mind it is more closely related to wavetable
> >>>> synthesis than
> >>>> either of the nonlinear techniques you mention (waveshaping and
> >>>> FM). I can
> >>>> completely imagine that it is difficult to control or predict
> >>>> what you'll
> >>>> get out. Experimentation is good, but sometimes you're aiming for
> >>>> something
> >>>> particular and it would be nice to be able to get closer.
> >>>>
> >>>> Thanks very much for a practical report on this.
> >>>>
> >>>> T.
> >>>>
> >>>> On 24 Mar 2010, at 03:46, Scott Nordlund wrote:
> >>>>
> >>>>>
> >>>>>> Simon Brouwer wrote:
> >>>>>>>
> >>>>>>> I see two other ways:
> >>>>>>> - using wavetables (very long ones)
> >>>>>>
> >>>>>> I'd discounted wavetables just because they would have to be
> >>>>>> very long,
> >>>>>> but memory is cheap, so why not.
> >>>>>>
> >>>>>> What about Wave Terrain synthesis? Is there an sdiy
> >>>>>> implementation anywhere? Load up a 2-d matrix with a surface
> >>>>>> of choice and then read
> >>>>>> linear subsections. Altering the start and end coordinates over
> >>>>>> time to
> >>>>>> vary the output waveform.
> >>>>>>
> >>>>>> -Dave
> >>>>>
> >>>>> I've tried wave terrain synthesis in Pure Data.  It's neat to
> >>>>> think about,
> >>>>> but the results I've gotten aren't drastically different from
> >>>>> FM or waveshaping or similar things (you could kind of consider
> >>>>> waveshaping and
> >>>>> FM to be subsets of wave terrain).  My implementation scanned a
> >>>>> surface
> >>>>> (defined by an arbitrary equation, F(x,y)) with a sort of
> >>>>> lissajous figure
> >>>>> that could be scaled, rotated, offset, etc.  To get something
> >>>>> decent sounding, I limited the surface and modulation to
> >>>>> continuous, bounded
> >>>>> functions (lots of sin, cos, atan).  A surface with
> >>>>> discontinuities or
> >>>>> singularities isn't going to sound so great.
> >>>>>
> >>>>> Anyway, yes, there's plenty of room for inharmonics and
> >>>>> animated and complex sounding things, and it's nice that any of
> >>>>> the inputs can be used
> >>>>> with envelopes or slow or fast modulation or whatever, but
> >>>>> there's also
> >>>>> a lot of unintuitive messing about to avoid sudden and
> >>>>> "unmusical" timbral
> >>>>> changes, or just to generally come up with something
> >>>>> interesting.
> >>>>>
> >>>>> The end result resembles something that might be more easily
> >>>>> obtained from
> >>>>> FM/waveshaping with arbitrary waveforms.  In fact that might be
> >>>>> a better
> >>>>> approach, because it's difficult to make an equation for an
> >>>>> interesting
> >>>>> surface.
> >>>>>
> >>>>> I'm not saying it's not interesting or potentially rewarding,
> >>>>> but it's not
> >>>>> the revelation that I'd hoped for.  Imagine FM with several
> >>>>> added layers
> >>>>> of confusion and obfuscation and you won't be too far off.
> >>>>>
> >>>>> _________________________________________________________________
> >>>>> The New Busy is not the old busy. Search, chat and e-mail from
> >>>>> your inbox.
> >>>>>
> >>>>> http://www.windowslive.com/campaign/thenewbusy?
> >>>>> ocid=PID27925::T:WLMTAGL:ON:WL:en-US:WM_HMP:032010_3
> >>>>> _______________________________________________
> >>>>> Synth-diy mailing list
> >>>>> Synth-diy at dropmix.xs4all.nl
> >>>>> http://dropmix.xs4all.nl/mailman/listinfo/synth-diy
> >>>>
> >>>> _______________________________________________
> >>>> Synth-diy mailing list
> >>>> Synth-diy at dropmix.xs4all.nl
> >>>> http://dropmix.xs4all.nl/mailman/listinfo/synth-diy
> >>>>
> >>
> >> _______________________________________________
> >> Synth-diy mailing list
> >> Synth-diy at dropmix.xs4all.nl
> >> http://dropmix.xs4all.nl/mailman/listinfo/synth-diy
> >> _______________________________________________
> >> Synth-diy mailing list
> >> Synth-diy at dropmix.xs4all.nl
> >> http://dropmix.xs4all.nl/mailman/listinfo/synth-diy
> >>
> >
> > _______________________________________________
> > Synth-diy mailing list
> > Synth-diy at dropmix.xs4all.nl
> > http://dropmix.xs4all.nl/mailman/listinfo/synth-diy
> >
> _______________________________________________
> Synth-diy mailing list
> Synth-diy at dropmix.xs4all.nl
> http://dropmix.xs4all.nl/mailman/listinfo/synth-diy