Wavetable Specs? (Custom)

tonymetcalf · March 23, 2021, 1:40pm

I know Serum typically uses wavetables of 2048 samples, and Surge can do wavetables with a crazy amount of waveforms. I’ve been searching but I can’t seem to find the specs for Vital’s wavetables. I want to start making some that are compatible with the newest emerging trends, and as tech gets better I can see a higher number of instantaneous samples becoming more common, so I would like to make them at 2048 but other software like Ableton use 1024. Since Vital is so new and popular I decided that it would be the deciding factor. Any info on that, and anything else I need to know? The more the better, I’m going hard on this stuff right now.

snfk · March 23, 2021, 4:47pm

My guess would be 2048 samples (but perhaps variable) -

github.com

mtytel/vital/blob/663ae7bb45849b2e3b0e144e5d4f4dd6cc7f799c/src/common/line_generator.h#L28




#include "JuceHeader.h"
#include "common.h"
#include "json/json.h"


using json = nlohmann::json;


class LineGenerator {
  public:
    static constexpr int kMaxPoints = 100;
    static constexpr int kDefaultResolution = 2048;
    static constexpr int kExtraValues = 3;


    static force_inline float smoothTransition(float t) {
      return 0.5f * sinf((t - 0.5f) * vital::kPi) + 0.5f;
    }


    LineGenerator(int resolution = kDefaultResolution);
    virtual ~LineGenerator() { }


    void setLoop(bool loop) { loop_ = loop; render(); }

No guarantee this is the correct answer though

EDIT:

github.com

mtytel/vital/blob/663ae7bb45849b2e3b0e144e5d4f4dd6cc7f799c/src/synthesis/lookups/wave_frame.h#L27-L28


static constexpr int kWaveformBits = 11;
static constexpr int kWaveformSize = 1 << kWaveformBits;

kWaveformSize = 2048

qub1t · March 23, 2021, 5:32pm

Open source ftw!

tonymetcalf · March 23, 2021, 5:39pm

Thanks! I was leaning in that direction anyway, already made some waveforms at that resolution. Now I just need to learn C++.

Tytel · March 23, 2021, 6:16pm

2048 is a good number. you get 1024 harmonics so you can play your oscillator down to 20hz before you start hearing the ‘end’ of the spectrum.

Also that bit of code is for line editing resolution (like LFOs) but it is the same 2048 for the wavetable.

tonymetcalf · March 23, 2021, 7:23pm

Wow! Thanks for the info and a little bit more. And I know you get this a lot but thank you for your amazing work. Inspirational.

snfk · March 23, 2021, 7:32pm

This was actually a good eye opener for me, I’m working on a wavetable synth right now and originally had the waveshape length at 4096 because it was just a safe number I thought would work for that time. Good to know and makes sense that 2048 samples will be plenty.

tonymetcalf · March 24, 2021, 8:28pm

Just came back to say good luck on your synth. People like you, Matt, and many others make me want to join the fray. It took him three years to make Vital, and maybe years from now people will be using your synth, or the next one you build!

Peter.H · March 27, 2021, 1:06pm

If you do the maths 2048 samples per slot is close to the number of samples you have for a cycle at midi not f1@44.1Khz (or so). So you can sample a synth from f1 (+/- some cents) and voila you can use that sample as a slot for your wavetable.
So all note above the reference note just “remove” some sample … on octave above f1 you can use half of the samples…ocatve above that a quarter … Just imagine a perfect sine cylce which is 2048 samples long … you need quite some octave steps and still there’s enough sample material available to rebuild the sine.
That’s why mostly all current WT synths use 2048 samples per slot, like Serum and Tone2 Icarus 2.

But in resmaple mode Vital is not locked to this interpretation of a “slot is 2048” long. Check out what happens when you resample a sample that was sampled at C4 … Tipp: WT Editor: Audio File Source and "Window Size" parameter - What does it actually mean
I did quite a few posts about wavetable, slotsizes and even pointed to some wt editiing software … think you can find it on your own