� ---------------------------- Original Message ---------------------------- Subject: [music-dsp] Antialiased OSC From: "Kevin Chi" <s...@finecutbodies.com> Date: Fri, August 3, 2018 2:23 pm To: music-dsp@music.columbia.edu -------------------------------------------------------------------------- > > Is there such a thing as today's standard for softSynth antialiased > oscillators? i think there should be, but if i were to say so, i would sound like a stuck record (and there will be people who disagree). � stuck record:� "wavetable ... wavetable ... wavetable ..." > > I was looking up PolyBLEP oscillators, and was wondering how it would relate > to a 1-2 waveTables per octave based oscillator or maybe to some other > algos. > > thanks for any ideas and recommendations in advance, if you want, i can send you a C file to show one way it can be done.� Nigel Redmon also has some code online somewhere. if your sample rate is 48 kHz and you're willing to put in a brickwall LPF at 19 kHz, you can get away with 2 wavetables per octave, no aliasing, and represent each surviving harmonic (that is below 19 kHz) perfectly.� if your sample rate is 96 kHz, then there is **really** no problem getting the harmonics down accurately (up to 30 kHz) and no aliases. even though the wavetables can be *archived* with as few as 128 or 256 samples per wavetable (this can accurately represent the magnitude *and* phase of each harmonic up to the 63rd or 127th harmonic), i very much recommend at Program Change time, when the wavetables that will be used are loaded from the archive to the memory space where you'll be rockin'-n-rollin', that these wavetables be expanded (using bandlimited interpolation) to 2048 or 4096 samples and then, in the oscillator code, you do linear interpolation in real-time synthesis.� that wavetable expansion at Program Change time will take a few milliseconds (big fat hairy deal). lemme know, i'll send you that C file no strings attached.� (it's really quite simple.)� and anyone listening in, i can do the same if you email me.� now this doesn't do the hard part of **defining** the wavetables (the C file is just the oscillator with morphing).� but we can discuss how to do that here later. -- r b-j� � � � � � � � � � � � �r...@audioimagination.com "Imagination is more important than knowledge." � � � �
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