I have mount surround sound in Ubuntu 14.04. When I am testing it with command:
speaker-test -Dplug:surround51 -c6 -l1 -twav
eveyting sounds fine but when I am using System Settings > Sound > Test Sound, the results differ. I got poor performance on right channels(right channels pause about every 0,5 sec). While listening to music I get this poor performance from the second test and I do not get why.