Yamaha DTXpress/DTXplorer/DTXtreme

I don't think any of the module settings will alter the choking - it
is really down to where and how you hit the rim.  If you want the main
cymbal sound, you need to make sure you don't hit the rim at all.  If
you want the rim sound, you need to hit the rim, preferably with the
stick at a fair angle to the cymbal (eg up to 90 degrees).  This is
partly technique, but also down to how you set the angle of the cymbals.

It is possible you have faulty cymbals.

Keith.