I'm going through a Sonar MIDI tutorial that uses Cakewalk Sound Center. In the tutorial, CSC sounds good. But on my computer (Win7 64b), I am getting a distorted frequency under the patch sound. And other sounds. I thought it was my speakers, but other MIDI synths don't seem to do this at all.
 
Is this something others have experienced?

I have the same problem as well. I get what sounds like an echo which seems to distort the sound. I am also on W7 64bit.
I think I have seen others report an echo problem.
I am using X1 producer.
 
It would be nice to get some response from someone if only, works ok for me. Does anyone use it?
 

Sound Center worked fine for me on my old Windows 7 x64 box, X1 Professional. It is still working fine on my new Windows 10 x64 box, Sonar Platinum.
 
Have you tried both ASIO and WASAPI to see if it makes a difference?