My blackberry curve has a high pitch noise coming from the speaker. Is that normal?

[u?l????]

I have a Blackberry Curve 8530 and I've noticed that there is a very high pitch ring coming from the speaker at the top. I tried to look it up online but a lot of people said they only heard it when the backlight was on. But I can hear this with the backlight on and even when the phone is turned off. The only time I don't hear it is when I take the battery out of the phone. Is there a solution to stop this ringing? It's driving me insane.