Pal,

Thanks for posting your specs in your sig (everyone who requests help should do this as it saves a bunch of time and wasted back and forth). See, now we're getting somewhere and I won't have to move all your posts to the Coffee House (whew, saves me a bunch of time). 


Your system looks good and its obviously put together well. This sort of thing sounds like it could possibly be an issue with the audio interface's driver. I've actually seen a similar issue with an older Roland interface which uses their older driver, but did not see the same issue with one of their new interfaces which uses their new driver, with the exact same project on the exact same system.


Maybe there was some change in X1 as to how it handles ASIO, I don't know for sure. Are you using the latest drivers with your Focusrite interface? If so, do you run ASIO or WDM? And at what latency? And what latency are your disk buffers and do you have read or write buffering turned on?


I assume, since Studio Cat put your system together, that you've got the Focusrite connected to a Texas Instruments firewire chipset?


SP

Hmmm, well you're not overly stressing your i7 system. Playback should be flawless with those settings. There could be a de-normal issue in one of the plugins you are using. I've seen that before, and what happens is you will see what looks like a spike or peak in the track or bus that the plugin is on, but no audio will play out of it or any other track or bus in the project. 

Do you see anything like this when the audio stops playing back? If so, you can narrow it down to a plugin or combination of plugins on a track or bus.

If not, this one could be harder to detect. The best thing to do would be to pare down the project one plugin/ synth at a time and try to repro it with as few as possible plugins to determine who's at fault. 

If it's a SONAR issue, then we might need to do some testing with a Focusrite interface, or maybe even your project.

SP

What's even stranger is this project is just one of several that I'm doing for the same client and all of them have just about the same makeup and plug usage.  In fact I don't think there's a plugin in one that's not in the others (I'll check that) and they aren't doing this at all.  So far, only this one project.  One common element tho is that it always happened while I was editing or moving audio in a plain audio track containing a mono vocal.

Yeah, you might be suffering from the "started in a previous version of SONAR" problem that happens. This has been around for a while actually. Sometimes SONAR gaks at an older project. Of course re-creating can be a royal pain if you've got a lot of stuff going on but it could free you from gremlins.