What kind of cloth pads are you using? Make sure there's no plastic or water-resistant backing on them -- those materials can trap in moisture and lead to odor. You can also use tea tree oil when you're washing the pads, as it's super antiseptic and can help keep odors at bay. And depending on what the odor is like, you may want to make sure there's nothing going on and check in with your doc.
I bought some Glad Rags and haven't experienced any odors. I'd try them again, as they're so much more comfortable than disposables. I'm a convert. I'll never go back to using disposables, ever!