It's hard to diagnose without being there. Of course surround channels don't always emit sound so it can sometimes be hard to "hear" if the surround channels are set too low. If you have a sound check system built into your receiver you could test them. I would guess that if you hear them on one setting they are probably working on all. There are a few places that the surround can breakdown. It could be the source material- not coded for surround. It could be whatever is playing the material, Blu-ray players for example can be set to NOT decode surround channels. It could be the speaker hookup so the decoded sound is not getting to the speaker. Finally it could be the unit transmitting the sound to the surround speakers. Make sure your source (Blu-ray, streaming device, etc...) is set for surround and that the decoder is actually decoding. You might want to hook the surround speakers up without the Rocketfish and listen for sound to help eliminate some possibilities.