hey guys, I have a friend that is not much on doing the online thing but he has a problem and cant figure it out and I told him I would try to help him by posting on here. he's a running a macbook pro from around late 2011 or so with Mavericks and Logic X. Apollo quad interface. He's using Superior Drummer 2.0 for drums. he always runs SD 2.0 on "multi-output" as he likes to mess with the individual drums. here's the issue; in the last week or so when he opens up an older project that has been created and has SD 2.0 for drums on a multi-output the kick drum is going crazy and I mean literally crazy. it's completely out of time with the song with no rhyme or reason as to what is going on.....turning plug ins on an off have virtually no effect on the kick drum. changing the buffer setting has not resulted in any better performance. however, if he converts the multi-output to a regular stereo output then the problem disappears.....?????? we are baffled......so if anybody has any advice on this it would be greatly appreciated. thanks in advance for your time.