Tune v/s Pitch shift v/s Time stretch, clarify on the mpc 1k

i been searchin and readin but its jus gettin more hectic confusing..

Can someone please clarify the differences in all that?

cuz I mean i can't pitch shift on the original os but what i do is Tune up/down and to me it seems to get the same effect that the homie on the computer gets when he does pitch shift..

but again in my research i come to find out that the new OS's for the mpc actually now have a feature called Pitch shift, that jus threw my thought process out the window..

so what exactly is the difference?

2ND thing is this...
somebody please break down the art of timestretching for me.. from my research and what i "think" i know. its basically allows you to change the tempo of a sample w/o changing the pitch of it... but what i dont' get then is this..

why if i have a sample that is 100bpm if i change it down to 90bpm..it sound retarded slow to the point of not being able to use it... i know i must be missing something.. but what i aint' know..

so if my sample is now at the desired tempo 90bpm how am i supposed to use it cuz its sounds slow or in worst case its then too fast...

i been at it like this for the last 3 months.. but its like nah son you gotta learn this other stuff too so you can take it to level 1 me being at level 0 still..

maybe i'm makin this harder then it seems.. but

thank you party peoples, i'm lookin forward to the eye openers on this.

oNe

tune changes the pitch of the sample. much like on a turntable, it actually plays the sample slower to lower the pitch, faster to raise the pitch. this has the side-effect of changing the length of the sample. (how long the sample plays back for)

pitch-shift is the "opposite" of and very related to time-stretch.

pitch-shift changes the pitch of the sample but keeps the length the same.

time-stretch changes the length of the sample but keeps the pitch the same.

so if you have a strings melody sample that is 1 bar at 93bpm and you are making a beat that is 93bpm...

tune the strings sample up or down and it won't match up with your beat any more.

pitch-shift the strings sample up or down and will stay on time with your beat

if you slow your beat down because flows better at 88bpm you would then time-stretch the strings to make them fit the beat at 88bpm.