Freq to rgb

    Jun 17 2006 | 2:21 pm
    hi all
    i'm looking for a simple way to convert a number, representing a frequency, into a list of three numbers, respectively Red Green Blue channel, respecting the correspondances between the audio and the light spectra. I've tried with some simple algos but whitout good results. Do you have any good idea?

    • Jun 17 2006 | 3:37 pm
      Depends on what you mean by good results. You may already be doing this...
      If frequency is a single number you can fiddle with it in various ways: unpack as three numbers using shift and mask scale the freq differently for each color plane scale the freq to 0..1 range then scale
      This is a basic problem of mapping sound to image and vice versa. A nice picture doesn't necessarily make a nice sound. I've used MetaSynth a lot for this but I have to design the image knowing what images make "good" sounds for me. I have not been satisfied with going from sound to image although manipulating a sonogram with jitter has produced some things I really like.
      You might also try fiddle~ and its cousins to collect spectral data from your sound mapping the fundamental and several strong harmonics into RGB. Envelope following is also useful as an input to the alpha channel.
      Cheers, Gary Lee Nelson TIMARA Department Oberlin College
    • Jun 18 2006 | 4:27 pm
      there are a few good ideas documented from about 1700-something to today, but most of them were not based on simple mathematic formula, but rather on sensibility of particular artist. I like the ones by Oskar Fischinger and Len Lye, but some people are pleased with mapping of freq to Hue and amplitude to Brightness or Saturation.
      best, nesa
    • Jun 18 2006 | 11:19 pm
      there is a work group of the AFIM wich works on the Visualisation of sound
      I think you will be interested in their work...
      Have a good time
    • Jun 19 2006 | 12:27 am
      Hi guys
      thank you very much for the precious infos! The main question didn't involve any sort of artistic mapping, this will be for sure one of my next steps, but my goal is only to rapresent a frequency from 20 to 18.000hz with a linear colours scale from red to blue or something similar.
      E.g.: an higher freq should be positioned in the range of the Blue-Violet if not standing at the synesthetic feels that probably wants to put an higher frequency within the Red range..and so on... At least i've tried simply using the Swatch object and that's works pretty good for me.
      Anyway the link about visualization of sounds shows an amazing project! I have ever been interested in this kind of synesthetic correspondances, from Skrjabin (a semi-scientific approach) and Kandinsky (a total artistic approach to sounds' visualization) to the contemporary goals on this ground as the mentioned O'Really videos on the Point Line Cloud's Curtist Roads DVD. Simply for discussing about it and share a little "OutOfTopic" opinion, i've recently seen an exibition by the duo tinylittleelements and i've found the video part as a really interesting interpretation of sound.
      Hope you can understand my bad bad english!
    • Jun 19 2006 | 8:37 am
      if you only want to map freq to color you can try this (just copy and paste it into a new patcher) :
      this is an adaptation of a little patch I made for the automatic determination of color. and you can get the freq of your sound object with fiddle~ (on MAC) or pitch~ (on PC).
      maybe it's what you need...
      PS : don't worry about your english, mine is not so good too...
    • Jun 19 2006 | 9:08 am
      thank you Antoine! This is exactly the scaling equation i need! Thank you so much for posting!