A question of frequency
  • One really cool thing I like about Audulus is that the fundamental oscillator node can be swept all the way from 0 to (half of) the audio engine frequency (22,050 on the iPad and 24,000 on my Windows desktop). That means, it can be used as both an audio oscillator as well as an LFO (and anything in between!). Most synth apps have a separate module for LFOs and audio oscillators. So I have two question:

    (1) Can someone list, of the 30 or so 'mainstream' iOS synths, which ones have similar full-spectrum configurable oscillators? I'm guessing we can count them on one hand.

    (2) Is there a 'frequency meter' node or module in Audulus 3? I've found the SampleRate node, but that just shows the audio engine clock frequency. What I would like is a meter that shows the frequency of a repeating waveform. I don't have the time, energy or knowledge to build a full-blown FFT module (but that would be a nice gift to the community if someone does!)

    Many thanks for any thoughts around this!


    -- Bryan
  • Try the zero cross node.
  • The frequency difference is from the sampling rate - iOS run at 44.1k, your computer is whatever the host is running at - you could run it higher if you had a higher sample rate set on your host.

    The meter that shows the frequency is a zero cross node - attach it along with a value meter and you have a frequency counter. But if you're just trying to read the frequency of an oscillator, just attach a value node to your Hz input.

    See attached patch for examples.

    Also, someone did an FFT already, but I can't remember who, and I can't find it on the forum, hah! sorry - someone else will chime in here probably.
    Hz Counters.audulus
    28K
  • I made a bunch of useful converters.

    Zero Cross Demo.audulus
    38K
    Hertz Convertz.audulus
    44K