1. Ensure you've selected the correct source.
Take a look at the options in the 'Source' and 'Second Source'.
2. Make sure your microphone levels are set high enough.
If you just have the mic selected in the BB FlashBack Recorder source control, this should be simple, but if you've got more than one source selected (as in the image above) it can get trickier. You can verify the mic levels by checking them in Windows:
- Right click the speaker icon in the Windows icon tray (bottom right of your desktop, normally) and select 'Recording Devices':
In the Sound window that appears, select the microphone you want to record from and click 'Properties'.
In the Properties window, select the Levels tab and make sure the Levels setting is set appropriately.