KVR Audio

petterdass · Post by **petterdass** » Fri Sep 14, 2007 10:00 am

HI

When listening to additive synths i hear they add sinewaves according to a specific scale, starting with octaves, then 5th and 4ths and then closer and closer as partials getting brighter. Which "scale" is this?
I know that for making saws etc there is also some rules about some amplitube getting inverse propotional to harmonic something... how can i best mimic this with adding sinewave subtracors in reason where amplitube is scaled from 1-127? (some fancy formula for this would be great, though i understand 1-127 is not accurat enough to get good results, )

This somehow confuses me with theory that saw contains every partial(or is it called harmonic in this case),like a 100hz saw is 100,200,300 hz sinewaves usually added up to nyquist frequency (is this what is called bandlimiting?)

Thanks!

johnny2johnny · Post by **johnny2johnny** » Fri Sep 14, 2007 10:04 am

hi, a question for the sound design forum perhaps... anyways buy this -----> computer sound design and synthesis techniques and programming...

by eduardo reck miranda.... because to explain what your trying to do would be a lot of typing...

whyterabbyt · Post by **whyterabbyt** » Fri Sep 14, 2007 10:14 am

petterdass wrote:HI
When listening to additive synths i hear they add sinewaves according to a specific scale, starting with octaves, then 5th and 4ths and then closer and closer as partials getting brighter. Which "scale" is this?

They dont, and it isnt a scale. Additive synths add sinewaves according to a user-defined set of frequency/amplitude/phase paramters per sine (possibly dynamic over time). Generally, most additives you'll find have no control over phase, and the frequencies are defined in terms of multiples of the fundamental frequency, ie they only do pure harmonic ratios. So that'd be f,f*2,f*3, f*4, F*5...f*N where N is the highest harmonic possible.

I know that for making saws etc there is also some rules about some amplitube getting inverse propotional to harmonic something...

More or less; the second harmonic has half the amplitude of the fundamental, the third harmonic has a third of the amplitude et.c.

Although technically, 'sawtooth' is just a general description. Not all sawtooths need be equal.

http://en.wikipedia.org/wiki/Sawtooth_wave

how can i best mimic this with adding sinewave subtracors in reason where amplitube is scaled from 1-127? (some fancy formula for this would be great, though i understand 1-127 is not accurat enough to get good results, )

Determine if the amplitude scale is linear or logarithmic. If its linear, that's easier. If not, do some experiments (0,16, 32, 64, 96, 127) to plot a rough graph of value versus amplitude, and use that as a starting point. Tweak your values by hand, and if you can, use something to display the output wave.

petterdass · Post by **petterdass** » Fri Sep 14, 2007 10:14 am

@johnnytojohnny

Thanks! I posted this also in sound design forum, but no reply so i tested here, what i was searching most was a "scale" for adding sinewaves, so i thought it might fit here,
Thanks for tips

jupiter8 · Post by **jupiter8** » Fri Sep 14, 2007 10:20 am

Check out the Wikipedia articles. They're a bit theory heavy but not impossible to decipher. With that said i think you're in for the "underwhelmed moment of the year" award trying to do additive synthesis with multiple Subtractors. But you'll learn something and experimenting and learning is a good thing. I just think there's a lot of work for very little reward soundwise.

johnny2johnny · Post by **johnny2johnny** » Fri Sep 14, 2007 10:34 am

well if you really must do additive synthesis than I will make a plug for my favorite synthesizer company... got check out " cube " on www.virsyn.net

this is additive synthesis* its very complicated is spec morph resynth... but its additive, and its all just very complicated, plz buy book to fully understand...

I own Tera 3 myself, and the man is a brilliant... Understatement.. brilliant synth designer...

jcivil · Post by **jcivil** » Sat Sep 15, 2007 8:57 pm

I agree with Jupiter on a lotta work for not so much joy with additive, but it's to learn how stuff works too innit. I think a lot of what you get result-wise with additive is got much more easily with FM.

kx77free · Post by **kx77free** » Sat Sep 15, 2007 9:17 pm

Hi,

Http://Kx77free.free.fr

I made the Kx-modulad synthesizer for the DC 2007

One of its principal feature is the WaveTracer, an external Additive program with some great features.

but, in the DC chat forum, I didn't receive any returns about this feature. I believe the Dc users don't understand the additive synthesis.

****

Kx-Modulad > select the Kx-WaveTracer panel.

full band 32 bit waveforms : 13.75 hz to 14080 hz (pitch avaliable).
up and more than 23200 hz (harmonics).
Up to 1687 harmonics for the low notes (13.75hz).
Same quality for all clock frequencies: 44.1 to 192khz (Kx-oscillators).
Level and phase parameters for the harmonics.
2 gibbs modes available (smooth waveforms).
easy to use (repeat mode).
With the Hi mode, the wavetracer calculates a lookuptable for each note!
no aliasing.

Help file

Thanks if you try it.

Xavier

jupiter8 · Post by **jupiter8** » Sat Sep 15, 2007 9:23 pm

jcivil wrote:I agree with Jupiter on a lotta work for not so much joy with additive, but it's to learn how stuff works too innit. I think a lot of what you get result-wise with additive is got much more easily with FM.

That was'nt exactly what i meant or said. I said doing it with multiple Subtractors is a lot of work for very little return.
It's like the old Kawai K5 where you had to manually set the amplitude for each of the 128 partials. That was about as fun as accidently setting your balls on fire.

With a plugin like Virsyn Cube or U-He Zebra2 where you can "paint" the partials it's not to bad.

Still my personal opinion is that additive is best together with a resynthesis algortihm. Takes away a lot of work that way.

jcivil · Post by **jcivil** » Sat Sep 15, 2007 11:41 pm

thanks for the clarification

Here's mine: by the time I get to sort a lot of maths, I forget what the point was in the first place (with an imaginary sound, which is all I have it seems).

an intuitive approach to additive, like a pencil tool to grow partials (eg: absynth) and build a waveform, is somewhat less problematic for me. I like if I get bored there I can try another way to find an analogue to my imagination (or a lateral twist to other possibilities), in there.

petterdass · Post by **petterdass** » Sun Sep 16, 2007 6:47 pm

jupiter8 wrote:doing it with multiple Subtractors is a lot of work for very little return.

I understand, but i like doing stuff with subtracor because most of my composition tricks is in Reason.
I just want to do extremely basic additive stuff and hopefully do some interesting composing with it. I also actually like the sound of sinewaves, so i think simple patches is good.

Is this some kind of scale? -24 -12 -5 0 +4 +7 +10 +12 +16 +18 +20 +22 +24
I found it in some additive patch on korg wavestation.

most basic additve synthesis theory