Roland SPD-SX Sampling Pad

I have so far had three of these .
The first one i got worked perfectly except the top 3 bar triggers (in particular the top right one) where not always triggering the sounds the way the 6 standard square pads did. { the top right hand one worked maybe 3 out of 6 hits}

I sent it back and got a replacement....same problem....the three bar triggers had to be hit with some consideral force before they would trigger, and even then there would sometimes be no response.

I sent that one back and have now got a third unit....guess what....yep...same problem.

Its not the velocity or dynamics settings as i have already been down that route.
As i said, the other pads work perfectly, the weight of the stick enough to trigger them, but those bar triggers!!
It could be just a bad batch as a friend of mine has one and its fine. (the weight of the stick triggers all pads on his)

Having said all that it is a marvelous piece of gear if you get one that works properly...as for me....im returning for a refund.