No sound from the subwoofer could be the result of a few different things. Check the below first before contacting SVS Customer Service.
Make sure the power cord is fully seated at both ends and that the AC outlet has power.
Make sure the RCA cable is connected to the subwoofer output jack on the A/V receiver.
Make sure the RCA cable is fully seated and connection to a line level Input on the subwoofer amp.
The subwoofer hard power switch is set to On.
You have held down the Feature Controller knob for several seconds on the Plus and Ultra subwoofers equipped with the 800W and 1000W Sledge platforms.
You have the volume adjusted to approximately 12 o’clock on the SVS subwoofers which have a rotary volume control.
You have the Volume set between -15 and 0 dB (the loudest setting) on SVS subwoofers which have a digital volume control.
In the A/V receiver set-up menu, the front channels are not set to Large/full-band and the subwoofer is shown as on/yes.
If there is still no sound from the subwoofer, please contact SVS Customer Service for more in-depth troubleshooting and assistance.