Evnabby
I finally got Soundcenter to produce a sound....then I go and add another synth and I can use the keyboards at the bottom to sample the sound...i didn't change any settings at all!!
I'm guessing there's a typo above and you meant to say "I can't use" rather than "I can use".
I just created a new project with Sound Center and Pentagon I.
After less than 30 seconds of tapping around on sounds with the little keyboard at the bottom of Soundcenter it went dead.
The thing about Sound Center is, it's a 32-bit Synth. Pentagon is 64bit.
If you are running Sonar 64 bit, then a utility called Bitbridge is going to be running in the background that allows you to use 32bit Synths' and VST's in Sonar 64bit.
One thing you can try is, fire up Sonar and load Soundcenter. Once you have Soundcenter running, Go in to Task Manager on your computer and find "Bitbridge.exe *32". Right click on it and go to 'Properties' then the 'Compatibility' tab. Check the box 'Run this program in administrator mode'. Also check the box that says 'Run this program in compatibility mode for' and in the dropdown menu below it, select Windows XP (Service Pack 2). Click apply and ok, then restart Sonar and give it another try.
I'm running Windows 7 64bit with Sonar X2 64bit.
This seems to have helped on my system, but I haven't tested it a lot.