High Pitched Ring

I have a general question, and this pertains to both Sonar and Band in a Box (it doesn't matter which music program I use). 
 
When I turn on my mixer and speakers, there is dead silence.  Very clear.  However, whenever I start up my music program (e.g., Sonar) there is a high pitched ring or tone.  I am doing ASIO and maybe that 'tone' is inevitable.  If not, is there a particular setting I need to use to get rid of it.  It does not come through on my recordings, by the way.  Only while listening to the tracks, while I'm recording, etc. (it's a background noise that does not copy over to my actual recordings).

OK... I have a mixer that runs to monitor speakers (Rokit 8s).  My ASIO thingy is a Stealth Pedal.  I don't use the pedal function but will plug in my guitar when recording.  When that item is plugged in, it makes the noise, whereas it's silent when not plugged in (I just discovered this because of your inquiry).  Obviously it's the ASIO device that allows me to hook up via a USB, or I'm presuming as much.  This Stealth pedal is from IK Multimedia.