If you are making a phone call with your Blackberry and a Bluetooth headset, the sound can be echoed because of a certain setting. The Echo Control setting can cause problems for some people when it’s enabled. Others have had trouble when it’s off. Either way, try playing with the setting to see if you get better results.
1. From the Home screen, press the Menu key.
2. Select Options.
3. Click Echo Control.
4. Change the setting to On or Off.
5. Press Menu.
6. Click Save.