Of the top of my head, there is also tablemix opcode that works well.
Tarmo

Anton Kholomiov, Jul 12 2016:

> I think that it's better to generate all three waveforms at the same time
> to get band limited result
> and then use `ntrpol` to crossfade between them:
...
Anton,
will this version result in a sound resebling a crossfade in loudness of two waves or can it sort of fade between the spectra?
...

Ta-ta,
----
Ffanci
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Emmett Palaima, Jul 12 2016:

> Hi, I am trying to figure out how to program an equation that when given a
> control value would cycle smoothly between a saw at one end, a triangle in
> the middle and a ramp at the other end.
Emmett,
I discovered a formula to generate a waveform approaching a sawtooth - or you can use vco2 - and I found a way to blend between sawtooth and square wave. I didn't, however, find a way to change the squarewave spectrum to resemble a triangle. But, PWM can be performed.

Does anyone know a method to synthesize a sqaurewave in such a way, that it can be changed to a triangle. I know that it can be done with additive synthesis, but that it too CPU hungry for my application. I thought about adding a lowpass filter in my tone generator. For that to work I'd need to know how to set up the filter exactly, which I don't. My waveform synthesis is based on a wave distortion method shown in a paper written, or co-written, by Victor Lazzarini. Unfortunately, I haven't discovered a good parameter tweak to morph from square to triangle spectra.

Any ideas perhaps? I'd be happy to share my meagre code and the general theory to morph between saw and square and do the PWM.
...

Ta-ta,
----
Ffanci
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The mathematical method to change a square wave into a triangle is 
integration...

Richard

On 12/07/16 22:20, Ffanci Silvain wrote:
> Emmett Palaima, Jul 12 2016:
>
>> Hi, I am trying to figure out how to program an equation that when 
>> given a
>> control value would cycle smoothly between a saw at one end, a 
>> triangle in
>> the middle and a ramp at the other end.
> Emmett,
> I discovered a formula to generate a waveform approaching a sawtooth - 
> or you can use vco2 - and I found a way to blend between sawtooth and 
> square wave. I didn't, however, find a way to change the squarewave 
> spectrum to resemble a triangle. But, PWM can be performed.
>
> Does anyone know a method to synthesize a sqaurewave in such a way, 
> that it can be changed to a triangle. I know that it can be done with 
> additive synthesis, but that it too CPU hungry for my application. I 
> thought about adding a lowpass filter in my tone generator. For that 
> to work I'd need to know how to set up the filter exactly, which I 
> don't. My waveform synthesis is based on a wave distortion method 
> shown in a paper written, or co-written, by Victor Lazzarini. 
> Unfortunately, I haven't discovered a good parameter tweak to morph 
> from square to triangle spectra.
>
> Any ideas perhaps? I'd be happy to share my meagre code and the 
> general theory to morph between saw and square and do the PWM.
> ...
>
> Ta-ta,
> ----
> Ffanci
> * Homepage: https://freeshell.de/~silvain
> * Twitter:  http://twitter.com/ffanci_silvain
> * GitHub:   https://github.com/fsilvain
>
> Csound mailing list
> Csound@listserv.heanet.ie
> https://listserv.heanet.ie/cgi-bin/wa?A0=CSOUND
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Richard, Jul 12 2016:

> The mathematical method to change a square wave into a triangle is 
> integration...
Thank you, Richard. I'll give that a go from within Csound and see where it takes me. Otherwise, there's always python.
...

Ta-ta,
----
Ffanci
* Homepage: https://freeshell.de/~silvain
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Try this:

instr 1
a1 vco2 1,p5,10 
a2 integ a1
a3 dcblock2 a2
   out a3*p4
endin

schedule(1,0,10,500,200)

========================
Dr Victor Lazzarini
Dean of Arts, Celtic Studies and Philosophy,
Maynooth University,
Maynooth, Co Kildare, Ireland
Tel: 00 353 7086936
Fax: 00 353 1 7086952 

> On 12 Jul 2016, at 21:26, Ffanci Silvain  wrote:
> 
> Richard, Jul 12 2016:
> 
>> The mathematical method to change a square wave into a triangle is integration...
> Thank you, Richard. I'll give that a go from within Csound and see where it takes me. Otherwise, there's always python.
> ...
> 
> Ta-ta,
> ----
> Ffanci
> * Homepage: https://freeshell.de/~silvain
> * Twitter:  http://twitter.com/ffanci_silvain
> * GitHub:   https://github.com/fsilvain
> 
> Csound mailing list
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Victor Lazzarini, Jul 12 2016:

> Try this:
>
> instr 1
> a1 vco2 1,p5,10
> a2 integ a1
> a3 dcblock2 a2
>   out a3*p4
> endin
Hey hey Victor,
this works really well, thank you. Unfortunately, there is still one feature that I can't realise with this solution: blending from a sqaurewave to a triangle. Is there a CPU friendly algorithm that can directly morph or cross synthesize between two waves? I think that the FFT based solutions wouldn't allow approximately  40 such operations in parallel on a 900MHz quadcore ARM architecture?

Does anyone know what a typical virtual analogue synth writer would do to create such an oscillator architecture? It was - I think - implemented in the Yamaha AN1X and, there was a setting for the Clavia Nordlead 3 that could morph from a sine to a saw. That would be quite sufficient.
...

Ta-ta,
----
Ffanci
* Homepage: https://freeshell.de/~silvain
* Twitter:  http://twitter.com/ffanci_silvain
* GitHub:   https://github.com/fsilvain

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