I wonder where to add a [line] here, and which one combined with what, not to have crackles when the START slider is moved.... I'm often stuck here

http://www.pdpatchrepo.info/hurleur/monosampler~.pd

try integrating [vline~] for smooth ramps. it works in the signal domain.

maybe attach a samphold~ from your phasor~ so that the start position only changes when the sound loops?

see attached edit

http://www.pdpatchrepo.info/hurleur/monosampler-edit.pd

Thanks sunji and mod for advice

mod, your Pd is high-level, i shall remind you to do a dollar sign tutorial

i have mostly finished it, just got to do one more bit. thanks for the reminder!