Wavetable creation

[dannytaurus]

@Lindon said in Wavetable creation:

how does the wavetable player know we are using (say) 2048 samples as our cycle size and not (say) 1024 ???

Short answer: it's clever.

Longer answer: it guesses the cycle length based on the correlation of slices. It starts at 128 then goes up in powers of 2 to 2048. If it finds a very high correlation in the slices at any one of those slice lengths, it returns that as the cycle length.

I suppose this only works on files that morph fairly slowly between waveforms. If your file has a cycle length of 2048 but each cycle is very different to the next, it won't find a suitable cycle length and will fall back to resynthesis.

Also, if your file happens to have Loop Range metadata, it will use that first, before any guessing or resynthesis.

[Orvillain]

@dannytaurus Do you know whether the mode used is resynthesis or resample?? Coz I tried the drag and drop thing, and the resulting wavetables did not sound great. Not as good as the ones I made in the resample mode inside Wavetable Creator.

[dannytaurus]

@Orvillain Looks like the full Wavetable Creator tries to find a cycle length from the root-note, but since the dropping an audio file into a wavetable synth doesn't have a root note it does it differently.

Audio files uses [1] metadata Loop Range, then [2] guess cycle range from correlation, then finally [3] resynthesis.

For simple 'traditional' wavetables, the audio file route is probably fine but for more complex ones the full Wavetable C reactor might be better, yeah.

The only reason I went down this whole route of using audio files is because I opened the Wavetable Creator and thought 'Nope!' . So when I saw using audio files would work for my use case I wanted to learn how to do that.

[Lindon]

@dannytaurus said in Wavetable creation:

I suppose this only works on files that morph fairly slowly between waveforms. If your file has a cycle length of 2048 but each cycle is very different to the next, it won't find a suitable cycle length and will fall back to resynthesis.

This is a bummer.....as I wanted to let the user drop in any wave file they liked, and including one that has no morphing between distinct 2048 long cycles.....

damn, Ok I feel a feature request coming on - a param that tells the wavetable player what the length is of cycles in the current loaded wav file..... how hard can this be?

[dannytaurus]

@Lindon How would you make sure the user's file has a cycle length of 2048?

[Lindon]

@dannytaurus oh I wouldnt ... I would have a param that the user can select from :

512
1024
2048

• so if they build their own wavetable wav file they would know it needs to be one of these values...
  and the UI would have a combo box allowing them to define the value they are using..

so the script call back would then include this new call:

WavetableController.setCycleLength(value)

[Lindon]

@Lindon whilst we are here....

what tool is everyone using to generate morphing wave files ?

so you have wav1 -> wav2 ->wav3 and you want to generate a bunch of morphs between these?

[dannytaurus]

@Lindon said in Wavetable creation:

• so if they build their own wavetable wav file they would know it needs to be one of these values...

If they're building their own wavetables, just have them put Loop Range metadata in the file which sets the cycle length.

Then they won't need to choose it from a dropdown.

It makes their wavetables more portable too.

[Lindon]

@dannytaurus said in Wavetable creation:

@Lindon said in Wavetable creation:

• so if they build their own wavetable wav file they would know it needs to be one of these values...

If they're building their own wavetables, just have them put Loop Range metadata in the file which sets the cycle length.

Then they won't need to choose it from a dropdown.

It makes their wavetables more portable too.

So how are they building their wavetables?

[dannytaurus]

@Lindon said in Wavetable creation:

So how are they building their wavetables?

Personally, I'd either use Vital (free VTS/AU) or I'd write a script that takes in 3 audio files of 2048 samples, then interpolates between them with audio file 1 as frame 1, audio file 2 as frame 128 and audio file 3 as frame 3.

[Lindon]

@dannytaurus said in Wavetable creation:

@Lindon said in Wavetable creation:

So how are they building their wavetables?

Personally, I'd either use Vital (free VTS/AU) or I'd write a script that takes in 3 audio files of 2048 samples, then interpolates between them with audio file 1 as frame 1, audio file 2 as frame 128 and audio file 3 as frame 3.

Well I assume you mean "audio file 2 as frame 2", but in any case..."interpolates" means what for a set of 2048 values(an array)?

if we work out the diff between any two value pairs and average the change over(say) 50 steps (essentially a cross fade) - this wont work as we will likely end with some zeroed value set at some point, and definately not a musical result..

hmm, interpolate here is tricky...

OK a bit of googleing gets me to:

https://www.sonicacademy.com/products/node