Thank you for your post and I can help you with this. When the channel volume is turned completely counter clockwise to the left there should be no sound coming from that channel. Now if the trim is all the way down and the channel volume is up you may get some audio through the channel. Please contact our technical support if you are still having issues. The L1 Technical Support line is 1-877-335-2673 in the US and Canada. If you are another country please go to http://global.bose.com/ and pick your country for service.