Creative Sound Blaster X7 Handbuch Seite 17

Select Speaker Impedance
The 4 ohm/8 ohm speaker impedance switch allows the Sound Blaster X7 to be configured to correctly
match the impedance of the passive speakers used.
Note:
Only applicable when Sound Blaster X7 is connected to passive speakers.
Warning:
To avoid damaging your speakers, be sure to select the correct impedance
rating that matches the impedance of your passive speakers.
Setting Up Your Audio Device - 16 -