a quick update on chasing whatever this noise is, it seems that it has nothing to do with any plugins, what i discovered last night was, while working on a drum track when i make any kind of change then hit the spacebar to play the track that's when the noise happens. i trying to figure out if the drum software (toontrack EZdrummer and superior drummer) have anything to do with it. toontrack is more softsynth then a plugin, it has it's own plugins.
what i'm going to do is pay attention to what i did to trigger the noise.
meanwhile, i've been using sonar's clean audio file and run a defrag/optimize in windows 10. in other words tune up the computer everyday. also, yesterday i contacted focusrite and downloaded a software update on the scarlett 2i2 i'm using.
that's what i have so far, and again, any suggestions will be appreciated. i'm reading and doing what everyone has suggested so far.
thanks again for all your time.
jp

Does it also happen if you click transport play in the gui, versus space bar?

that's a good question, i thought of it last night and it's one of the things i'm going to watch today when i start working.

Have you got your onboard audio disabled?

yes, i have disabled the computer sound. it happened once yesterday and i noticed that i had a track armed to record and inadvertently hit the spacebar instead of the record button in the transport.
i'm going to keep tracking this down
thanks everyone
jp 

What's the nature of the noise? Hiss? A high-pitched whine? Aliasing?

the best way to describe the noise is, you know when you're plugging in your guitar when the amp is running (off standby) and one gets that noise until the TS jack finally gets into the jack in the guitar. that's it.
what i've been doing is really paying attention to what i'm doing and what all the parameters are right before it happens. like the other day, i had a track armed to record and i inadvertently hit the space bar, and no, i have not tried to replicate it, maybe i should.
i would appreciate any ideas or thoughts you may have, and thank you for responding.
jp