PrimeLimitConformer (ratio quantizer)

« »
  • Download Info

  • This class is one I use the most. I'm always reaching for it. And it doesn't have any audio output. It's a Capytalk thing really, packaged up as a Sound.

    It might have a weird name but what it does is a straightforward idea. It forces a !HotValue to a simple fraction or whole number. It's easy to force a fader in the VCS to whole numbers just by setting the control's grid. What this Sound does instead is force the !HotValue to a simple ratio. For instance 1/2,  3/4,  16/9 etc.  I find these simple ratios really musically useful.

    The way you specify the allowed ratios is using a "prime limit" which is something you might hear about if you're using just intonation. The prime limit is the largest prime number you can use to make the ratio. The ratio is constructed by using primes up to the limit and taking them to a power. For instance:

    2**2 / 3**3 = 4/27

    Even using a prime limit there is still an infinite number of ratios you can create by using ever higher powers, which isn't useful as a quantizer. So in my class you also specify what the maximum coefficient is, which then produces a finite set of ratios.

    This class also lets you control how strictly you want to force to these ratios using the Conform parameter. If Conform is set to 1 then the Sound forces its output !HotValue to precisely the allowed ratios. If Conform is 0 then it passes the input !HotValue straight through without quantizing at all. With Conform set between 0 and 1 it will constrain to the allowed ratios with some wiggle, which is nice for a more natural pitch quantization with a bit of variability.


    In the audio example I'm using two PrimeLimitConformers to perform the tune using two knobs on a midi controller.

    Topic Posts Last Poster Updated
    No topics