Creating non-sinewave overtones

    Feb 25 2013 | 12:11 am
    I've got an idea for creating a new type of synth. Most synths use waveforms to generate their sound, but I want to control the harmonics/overtones myself and simply have them repeat at descending values up the sonic spectrum. I want to use a graph to shape an overtone, run it through white noise to actually create the sound of the overtone and then have it play at every octave above the note that's being played. Is there any way to do this?
    PS: I don't really need people asking me what the point of this is or that there's an easier way of doing it. I know what I want and simply need some advice on what objects can be used to it.

    • Feb 25 2013 | 12:45 am
      You need to be a lithe more precise with how you envision this "new type of synth" to function. You start off pretty much describing additive synthesis but you don't want to use sine waves. Then you describe something sounding sort of like subtractive synthesis, but it's not entirely clear what you really want.
      I think if you can reword what you mean when you say "run it through white noise to actually create the sound of the overtone…" we might get closer to what it is you're trying to accomplish.
    • Feb 25 2013 | 12:56 am
      I want use a graph (mathematical, like for coordinates or in math textbooks) to create a filter. This filter will be used on white noise. This will create an overtone with a unique shape, causing the sound to be slightly different from a sine wave. I will repeat this filter once every octave. I will then layer these harmonics with different pitch intervals to create a new timbre.
      How do I create these filters?
    • Feb 25 2013 | 1:08 am
      Look at the reson~ object or the resonant filter type for the biquad~ object for the filtering. Then it's just a matter of tuning the filters to the overtones you want. You could make each consecutive filter set to a center frequency that is a multiple of some fundamental that you set or play via MIDI.
      I think Stefan Tiejde has done something similar with his ST.ascade M4L device:
    • Feb 25 2013 | 2:38 am
      While that would allow me to create multiple overtones with a filter, it still wouldn't let me design the shape of the filter.
    • Feb 25 2013 | 3:29 am
      Have you looked in the examples/fft-fun folder? There are a few patches there that might give you some ideas, e.g. forbidden planet.
    • Feb 25 2013 | 7:47 am
      i am not sure why you would repeat the filter once every octave, shouldn´t it be repeated at the frequency of every overtone?
    • Feb 25 2013 | 12:27 pm
      maybe have a look at cnmat's resonators~ object-- i think it will help you with what you want to do. it takes arbitrary lists of frequencies, magnitudes & decay times to filter an arbitrary signal (like white noise)
    • Feb 25 2013 | 3:46 pm
      It seems I'm working on exactly what you are trying to achieve.
      It uses cnmat's resonators~ as Terry suggested.
      you can have a look to the description of the system and two little sound samples using filtered noise as input
      for english translation
      I'll hopefully make it available soon.