Spinback effect sounds unnatural

[Daniel Schürmann]

Mixxx has a spinback effect, accessible via controller only (script.spinback)
It accelerates the track backwards when pressing a mapped button and plays the track afterwards.

My expectation is that it sound like pushing a vinyl backward with a sharp acceleration an a spin down phase afterwards. Something like demonstrated here: https://www.youtube.com/watch?v=dzEJoSkwvnI at 0:20. This is not the case, right now.

I think the effect should follow a turntable inertia model. This can be also used for spin up and down effects.

[ronso0 (ronso0)]

To clarify:
currently the backward spin kicks in instantly.
When doing a manual backspin though there's a short ramping from current playback speed (or halt) to fast backspin.

[ronso0 (ronso0)]

An inertia model would also fix
lp:1812483 improve engine.softStart, brake & spinback

Related bugs/feature request:
lp:692928 Brake effect on stopping a song (without controller)
lp:1692261 make brake, soft start, and spinback part of the effects system

[Swiftb0y (swiftb0y)]

Mixxx now uses GitHub for bug tracking. This bug has been migrated to:
https://github.com/mixxxdj/mixxx/issues/10700