• oscinv~: osc~ but with the concavity inverted

(First, thanks, @seb-harmonik.ar for the tip. Really appreciate it.)

Originally I thought of doing this just as sort of challenge, to see if I could get it worked out and thought given the current pantheon of wave generators perhaps we could use another one.

What it does is invert the curvature of the osc~ wave form so in a quadrant of the wavelength where it normally curves down, here it curves up, and vice versa for the other two quadrants of the wave.

(more pics below)

It's accomplished by aligning the original osc~ with two square (phasor~) waves: the first to get the shape right (one wavelength for each quadrant of the original wave (so 4x the freq) and a second square wave to shift the wave up and down in the quadrants that need it.

The help file is setup to allow you to hear the difference between the osc~ and the oscinv~. (Note: if you change on the fly, the table does not write properly (i think (unless someone can tell me otherwise) because of the discrepancy/lag between changing the frequency value and the writing of the table).

The resulting tone is Very different than the original pure osc~ tone and it seems to me it has some sort of resonance(?).

If not usable, I hope you enjoy the thinking that went into it.

(It was a helluva of a lot of fun to work on. *Once I got the sucker! ).

Peace, happy pd-ing to one and all.

Sincerely,
Scott

p.s. oh, it has one inlet (frequency) and one creation argument (also frequency) and sends out a ~ signal.

p.p.s my thinking is those who make and/or use synths (esp.) might have some use for it.

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• Hi. The Yamaha DX11 uses a wave like this in order to generate more harmonics in an fm setup that uses 4 oscs instead of 6.

In pd, it might be more efficient and less alias-prone to reach an audibly equivalent result by doing some light self fm like this, which sounds almost identical to my ears anyway:

If you are doing some kind of intermodulation, there might be some differences, but it'd be best to test by ear first if you're making a synth - to see how they differ audibly. I've played with wave shaping a lot and it took me a long time to realize this. Upper harmonics tend to be perceived as upper harmonics no matter what the actual waveshape is. That's sort of a cynical take but it's been useful for me personally.

I was interested in shaping the oscinv with a single phasor object and played around with clip~ and wrap~ for a while until I stumbled onto a table as a piecewise deal to invert and shift a native cos~ around. I'm attaching this. It could be tweaked to generate other curve table mixups like on the dx11. To get W5 - W8, you'd need to expand the piecewise table to 8 values.

piece.pd

• WOW, @LarsXI! Your piece.pd (above) is Sooo much more elegant!

Also, cudos @seb-harmonik.ar I am pretty sure this is what he was trying to tell me (when I asked for help on another thread) but I am too ignorant in so many ways about pd.

It has also proven to me the Maxim:

The more you learn, the more you realize how little you know.

And it's corrolary:

The pd-family contributes so much, whether asking/begging (:-) for a little help or suggesting a new or different way to look at the flow of audio-visual signals. And are some of the nicest, most generous people I have ever met (neck-and-neck with the Puppy Linux Community.

There is so much I do not know about audio theory (honestly? Pretty much everything you said went right over my head, except "synth" and "Yamaha" .

On the other hand, I do know enough to determine when a solution is "elegant".

Thank you, both for the education.

Suggestion @LarsXI : abstract this out and share it as a waveform-selector. (The 8 not the four). Think there are others who either don't comprehend this or could use an absraction that they could plugin-and-play and select the wave-forms out of the box. (If it hasn't been done already )

Peace, Love, and KNOWledge flowing out of us all.

Sincerely,
Scott

• @svanya Since the TX waveforms were mentioned (and the waveform you are looking at producing looks very much like W2), I was also interested in generating those at some point. Here you find an excellent patch by @katz to generate those to a table if it helps.

https://forum.pdpatchrepo.info/topic/10735/yamaha-tx-waveforms

• Ah! here's a way to do it with samphold~ !!
shpiece.pd

@svanya, I've spent so many hours staring at single phasor~s plus vanilla audio math. I've hit some walls and given up on projects for years and years. I always used to avoid using tables because I had signal inlets working on the oscillators, but now I'm finally getting used to tables. Tables can definitely lock you in though for certain synthesis tasks! Your approach of multiple phasor~s in a context where it would be interesting for them to be out of tune/phase would be the only way to go.

like here's a silly example of something you could do with multiple phasor~s that wouldn't be possible to do with a table.
phasemod.pd
I have to stress though- the results of this kind of thing often sound identical to simple fm. So unless you're really onto something, you might be best off using wavetables and fm.

• Cool! I did this exercise almost exactly, building the TX waveforms in Audulus. This will give me a good way of comparing how nodes work in Pd. Many thanks!

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