Logic Pro 9 Using Logic 9 live problems


New Member
Hi everyone, my name's Scott. I'm brand new here although I've been using Logic for years. I have a couple of problems that are making me scratch my head at the moment and I'd be extremely grateful if anyone has any ideas to fix them. I'll try to be concise but please forgive me if I end up being a bit long winded.
I'm about to do a duo gig with a singer and I'll be running backing tracks on Logic with me playing keyboard plugins in Logic. I'm mostly using Spectrasonics Trilian and Omnisphere with some other samples on the EXS24 and one or two other things. I've set them up in the environment throught the physical input and monitor. The first problem is when the track's running the first note I play comes in late - like a glitch - it's definitely not latency as subsequent notes are fine. And if I don't play for a while with the track running the first note I play will glitch again. At first I thought this was a problem with the Spectrasonics synths but it happens with the EXS and other plugins too. I've messed about with buffer settings for hours but nothing makes much difference. Anyone know what's going on here?
The other problem is that at the start of a song I hold a chord then start the track but Logic cuts the chord dead. Really frustrating. Is there any way round this?
Thanks very much for reading and I hope you can help.

I'm using a 2009 macbook pro 13, 2.53 Core 2 Duo, 8 GB Ram, 750 GB HD, OSX Mavericks.