Greetings All,
During my first time mixing down some tracks with X3c, I now get a high frequency tone added during Export Audio...
 
All "Export Audio" settings are identical to settings used in Sonar 8.5 and earlier, as well as X1d and X2a:
Files of Type = Wave
Channel Format =  Stereo
Sample Rate = 44100
Bit Depth = 16
Dithering = Pow-r3
All Mix Enables checked - except Fast Bounce (Audible Bounce/Live Input are grayed-out)
 
This same setup has worked on this same machine with X2 and X2a without a single issue.
 
With X3c, I now get a high frequency tone added when exporting audio (mixing down).
The tone starts in the blank space before the music starts, and continues throughout the entire song.
 
No extraneous inputs/feedback/or tracks are showing this during play, and X3c plays the tracks just fine -
with no tone added.
 
Has anyone else experience this yet?
 
IF - I UNCHECK "64-bit Engine" in the "Mix Enables" section of the Export Audio window, the problem/tone goes away... 
 
Most would say to run with that, but why is it now an X3c issue that prohibits me from using the 64-bit processing engine during mix-down?
 
Is this a known issue with X3c?
 
Thanks,
MG
 

There were issues introduced in X3c solved by disabling the 64bit engine; for example, using the PC Console Emulation on a track with mono interleave. It sounds like you have at least one of those issues in the project and have stumbled upon the temporary fix.

Yes there is an issue and the bakers are working on a fix, please wait for X3D patch which will probably be with us by the end of the year. For the moment your PC will work perfectly happily with this 64 bit feature disabled and you will not even notice it.

Roger that.

Thank you both for your helpful responses.

Cheers,
MG