Phase or Frequency modulation for newbie?
  • Hello, I'm new to Audulus, eager to learn more.
    Is there a preferred way to make FM or PM? I've tried with some basic math expressions, and experimented with frequencies and stuff, but haven't seemed to get it quite right yet. Thought I'd ask in case there's this obvious use of modules where it's all easy :)

    Awesome app btw.
    Ps. I'm on iPad.

    Cheers
    Cuckoo
  • I usually copy and paste the fm and pm stuff when I make an oscillator for a patch. Here is a patch I made with some phase modulation. I will also post some modules that I think might be useful to play with.
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    phase feedback voice.audulus
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    Linear Zero-Crossing FM Oscillator Mk V.audulus
    90K
    Mini Osc.audulus
    22K
  • This is my first FM thing that's seems to sound legit. But it might be a rudimentary way of doing it. Gonna check out your files too @RobertSyrett Thanks!! And great stream yesterday by the way! Gotta catch up and watch the whole thing later today.
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  • Wow @RobertSyrett Those are some advanced patches. Gotta take some deep diving to for fully understand what's going on underneath. That last one, "Mini OSC" sounds great!
  • This is the DX-7 Algo Clone I'm working on right now - it's not all the way finished, but getting there!

    FM Audulus.audulus
    1M
  • @biminiroad woah, that's an insane patch! Sounds beefy and cool.
  • That's crazy stuff @biminiroad. As usual that is going to be an awesome display. Also, where are the oscillators hidden? All I see are envelopes and switches!

    @cuckoo Thank you compliment, also your profile pic is amazing. Feel free to post any patches that aren't working as you expect. I'd be happy to revise and make notes.
  • Thanks @RobertSyrett Here's a little first pseudo FM-synth. It kinda works and sounds like FM, with my simple "vibrato" approach. Baby steps
    FM 1.audulus
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  • @cuckoo As expected you have a firm grasp on the math behind FM, now that I think of it I learned to decipher FM algos from one of your videos. I would just suggest a few differences in patching that will make your life easier in the long run. Basically keep the knobs 0-1 for easy modulation with LFO's and try using the phasor oscillator with FM patches as it is more flexible.
    FM1 annotated.audulus
    51K
  • I was watching a youtube video on FM4, the iPad app and thought it would be great to play around with the waveforms that app has in Audulus.
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    Unfortunately, the best way to get them to work with phase modulation is the spline node, so these waveforms are less than mathematically perfect. They have a rather hand-drawn quality, although the spline grid, that @stschoen made, facilitated evenness greatly.
    image

    These operators are very CPU efficient so they stack nicely in all the familiar algorithms.

    I'm always looking to improve and thoughts about how to make phase modulation friendly versions of the spline waveforms are welcome.
    PM1 osc.audulus
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    2 OP algo.audulus
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    Screen Shot 2017-07-27 at 3.49.32 AM.png
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  • The spline window is great! Would be great if one could draw a spline with maths with curve precision, and calculate it once to save CPU. Like use simple sin cos abs formula variations to get smoother curves. I just experimented with some basic trigonometry maths here to see what these curves are made out of. Perhaps hand drawn end up with more useful character, but anyways.. here's to maths!
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  • @cuckoo I actually made that version first! But it sounded rather strange with phase modulation, much more like a pulse wave. When I looked at it on the oscilloscope I could see that something was amiss. But it did work fine with thru-zero FM so I've uploaded that version along with an updated version of the spline-based oscillator. Just know that the phase input on the expression node is really some other type of modulation.

    It would be great if we could calculate it once and save CPU, but I think that will have to wait for the data node (which will be able to be used a wavetable) to come to Audulus.

    NOTE: "1/o" input is really more of an exponential FM input, so if you want it to track to other "o" modulation sources set the Hz to 440. Also, if you want to have less extreme FM, there is a trim pot inside the osc that will change the index.
    OPERATOR.audulus
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    SPLINE VS EXPRESSION.audulus
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  • I reworked the expression version of the operator so it now is responds the same way to phase modulation input as the spline version.

    edit: 8/9/17 - corrected an error where the hz output was actually a sinewave. That should help with maintaining ratios ;-)
    OPERATOR v0.5.1.audulus
    120K
  • I really need to get down to the core with audulus. Have patience. It'll happen! Suddenly I'll spend a few days non stop to get a better understanding for all building blocks. It's such an elegant app!