IF the info on ring tone does not work read the link for detailed info on sound settings.
If that does not work use the second link to see if you have additional issues.
Change your ring tone
1. On the Home screen, click the Sounds icon.
2. Click Set Ring Tones/Alerts.
3. Click the application or item that you want to change.
4. Perform one of the following actions:
To use a preloaded ring tone, in the Ring Tone field, click a ring tone.
To use a ring tone that you downloaded, in the Ring Tone field, click Select Music. Navigate to a folder that contains ring tones. Click
a ring tone.
5. Press the Menu key.
6. Click Save.
8520 manual http://btsc.webapps.blackberry.com/b...ListHelperImpl
trouble with tones KB24307-Ring tones and alerts do not play regardless of the tune or volume setting