Strudel, how to do a progressive fade out

Strudel
1

I started experimenting with strudel less than a month ago (I'm a beginner), but I haven't seen any examples of how to do a fade-out to smoothly end a track.

For now, the most "elegant" solution I've come up with is the following:

all(x => x.when(
   time.gt(5),
   y => y.postgain("<1!6 0.75 0.50 0.25 0.1 0!1000>")
))

If we want to fade-out after cycle N, we have to use

all(x => x.when(
   time.gt(N),
   y => y.postgain("<1!(N+1) 0.75 0.50 0.25 0.1 0!1000>")
))

We use postgain, instead of gain, so that tracks with a defined gain don't jump to gain(1) when the fade-out starts, but rather remain relative to their current volume.

If you can think of a simpler way, please let me know.

2

A few things:

You can use the filterWhen function to enable/disable a track based on the global time.

You can use mul to multiply the existing gain/postgain values instead of setting them, preserving any previously set values on the pattern.

Combining this, we can easily create fadeOut and fadeIn functions:

register('fadeIn', (start, end, pat) => stack(
  pat.filterWhen(t => t >= start && t < end).mul(postgain(saw.slow(end - start).late(start))),
  pat.filterWhen(t => t >= end),
))

register('fadeOut', (start, end, pat) => stack(
  pat.filterWhen(t => t < start),
  pat.filterWhen(t => t >= start && t < end).mul(postgain(isaw.slow(end - start).late(start)))
))

As you can see we simply create a stack that has 2 patterns: 1 that plays normally when that pattern is supposed to play, and another that modulates the postgain from 0 to 1 or 1 to 0 over the correct number of cycles.

Because we're using mul to apply the postgain, you can use this anywhere without breaking existing volume controls on the rest of the patterns.

3

As I mentioned, I'm a complete novice with Strudel. Thanks for your comment; your approach is definitely much more elegant (and allows it to be applied to individual tracks).

I was unaware of the existence of .filterWhen(), .isaw, and .late().

You've also just solved another question I had (how to generate progressive values linearly).

Thanks for taking the time to reply.