Has anyone noticed noise on Piano Real Tracks?

I've experimented with these RT's: 831, 1701, 2049, 2117

There seems to be a hiss and/or a background rumble that I can detect on my KRK monitors and with headphones. I don't detect that same noise on other Real Tracks I'm working with. Violin or mandolin for example.

The noise is present on RT's in BIAB, in RB, and on those tracks imported to my DAW.

I don't rule out a hardware or settings problem, just starting here.

Thanks.

My songs are here:
https://soundcloud.com/scott-h-olson