20 Hz Modulation in Synth Audio Out

I've a 20 Hz modulation in my synthesizers ...  Strobe 2  and,  I discovered, probably in others as well.   I know not where it is being generated.  I suspect  that somewhere in my SONAR Platinum.  Here is a link to the waveform audios (wave files) as well as screen shots (jpegs) to help diagnose the issue.
 
Any help is most welcomed!

 
 
Thanks for the suggestion.  I didn't succeed in trying out the Synthesizer using another DAW ; but, I did exercise the Audio channel  with no MIDI Synthesizer using True Piano.  No Key Studio Input  ... i.e., just using the virtual keyboard in True Piano.    I recorded the waveform  and heard that the 20 Hz modulation  was still present. So it is something, I suspect,  that is implicit in my SONAR Platinum setup. I am not terribly knowledgeable about all the ins and outs of Platinum but I must have some parameter screwed up.
 
I've added the TRUE PIANO Waveforms to the Link cited above. The modulation, as you might see, is one of there being no audio out for 10 milliseconds  at the 20 Hz rate. It is doubtful; but, could it have something to do with latency?    

Are you using ASIO or WDM driver mode?  Looks like you might have to increase the number of audio buffers or even update your audio interface drivers.