hr.~ high resolution objects


    Jan 18 2006 | 4:54 pm
    hi
    if i am making an FM synth, am i going to get a better
    sound by using jkc's high resolution objects than 32
    bit ones? or is it mainly the sample rate thats
    important....?
    thanks
    james

    • Jan 18 2006 | 9:41 pm
      These objects were primarily designed for generating accurate sub-
      sample values for reading from large buffers, and filters where 32bit
      precision weren't adequate for filter coefficients. If your FM
      algorithm contains feedback, you might find that these objects
      provide results with less accumulation of quantization error, though
      whether or not that is even a problem or sounds "better" is obviously
      dependent on what you're doing, and what your ear prefers. I would
      recommend using the standard objects first, and then perhaps
      experimenting with the hr objects to see if you can notice a
      difference. For FM, I'd imagine you won't notice a large difference,
      however I'd be interested to hear your findings.
      -Joshua
    • Jan 19 2006 | 10:05 pm
      I think the sample rate would make a big difference for
      high frequency FM. The higher the sample rate, the fewer aliased frequencies appearing in the audible range. I can't comment on
      quantization error or how much difference it would make.
      If I were you, I'd forget FM and just go with Phase Modulation instead. Once you start builing complicated FM stuff (multiple carriers/modulators interacting with eachother), it starts to sound like crap (imho), especially with feedback. I can't give a DSP math explanation as to why. Russel Pinkston wrote in the Csound book that complicated FM can introduce DC offset (I can vouch for that) and carrier drift.
      Here's an example of 1 carrier, 1 mod PM with feedback:
      max v2;
    • Jan 25 2006 | 1:20 am
      thanks for that patch
      i had a mess around with replacing all the FM with PM
      in my synth patch, and it sound sharper, but not
      necessarily better. for instance with FM you get a
      pitch wobble on attacks as the oscillators drift from
      the fundamental, but that actually sounds sort of
      realistic. the PM sounds alot more synthetic to my
      ears, which i guess could be good sometimes.
      i'd be interested if any one else has experimented
      with PM versus FM synthesis
      cheers!