High pitched vocal distortions w/ amplification

Hi folks,
I’m totally new to any kind of audio work and I’m not really clear on all the right terms. I have run into a similar problem before, but currently I’m working with a somewhat quiet vocal track (just somebody talking). When I use normalize and amplify the track very faint high-pitched metallic sounding distortions can just barely be heard mixed in with the voice. After using bass boost the distortions grow louder and are plainly audible. Because of their high pitch, I thought maybe I could get rid of them by using a low-pass filter, but that doesn’t seem to be working. Are there any common causes for this sort of distortion? Anything I can do to prevent and/or remove it?
Many thanks for any advice!

high-pitched metallic sounding distortions

Without actually hearing it, I bet someone has tried to apply noise reduction to the performance. That’s about what it sounds like when you do it wrong.

No, you can’t easily take that out.

Do you have control of the original shoot?


Thanks for responding. You are right. I did use noise reduction, and could have easily done it wrong just using default settings. Also, I do have the original recording. Do you have any suggestions?