Cricky sound...

Hi all, I believe this is my first post in the digital pianos forum, so let me introduce myself.
I am 16 years old have played for 2 years and am learning Schubert's impromptu Op. 142 #2. Okay, now that that's done, here comes my problem.
I have a year-old Yamaha Clavinova CVP-201, and it's been pleasing me immensely until now.
Sometimes, when I play I hear a "cricky" sound (go ahead, say it aloud, emphasis on the R). It doesn't happen on a specific note, I think it's when I play around forte. It also happens when the volume bar is at the lowest.
Does anyone have any suggestions on what I could do for this tiny, yet irritating problem?
zorro

What level do you have your volume control at? If you are only hearing the problem at forte, and your volume is a little high, it may be your speakers. Sometimes on smaller digitals, if you are playing too loud, the speaker can crackle and distort. Do you hear the problem with headphones?

The volume's at medium. I'll have to check for the headphones.