Akai s950 + roland mc500

How do you loop the sequence on the mc500 mk2?

I asked to a "roland expert" and he solved my Problem.
"The trick is to set the repeat zone not by bar numbers but by LOCATE points.

If say you want to repeat a 16 bar loop from Bar 33:

Set your Locate Points, by going to FUNCTION 10.
Locate point 1 will be the start of the loop. Set this at 33 - 01 - 000
Locate Point 2 will be the end of the loop. Set this at 48 - 04 - 095

Go to FUNCTION 7 to set the Repeat zone:
Here, instead of entering "from bar 33 for 16" in the Bar display, you hit LOC to bring up the Locate Points display, and enter 1 and 2.

Done.

Now, when you hit SHIFT + PLAY you will play a 16 bar loop with no glitches.

This is because the point 48 - 04 - 095 is the last "tick" or "clock" in those 16 bars. If you do it using bar numbers, the first "tick" of the next bar gets included in the loop, in this case 49 - 01 - 000, which throws it out."