Trying to obtain a clean sub-only bass on m_S

Greetings, i’m looking for a way to make as such totally clean( distortion free) sub only sounds.
the closest i got to it was using a sine wave from factory sounds, yet, if i move. sample start from zero it suddenly turns into a square wave,
other clean sounding sub samples (on my laptop) wont do the same trick when played back on the model samples, even here there is something to do with looping but i struggle to understand what

look up @minimal.camera s videos on youtube, he explains the looping technique really well