bellVolume resource

From The x3270 Wiki
Type Default Option
integer 0

Controls the volume used when ringing the terminal bell. The value ranges from -100 (silent) through 0 (normal) to 100 (loud). Not all X11 servers can vary the bell volume, other than turning it on and off. This resource can be overridden by the visualBell resource, which if true, will replace the audible bell with a flash of the screen.