A:Answer Your understanding of 5.1 is the correct understanding of the 5.1 term (2 front [L & R], 2 rear [L & R], one center, plus subwoofer). Samsung's use of 5.1 is non-standard. They have 5 speakers in the sound bar: 2 front, 1 center and two side firing speakers, one in each end of the bar. I'm sure that the front & side speakers (the left side pair or the right side pair) are linked so the same sound (either the L sound channel or R sound channel) comes out of both speakers.
A 2.1 system means L & R speakers and a sub (referred to as ,1), A 3,1 system is left, right, center, and sub. After 5.1, the next most common system is 7.1 which is L/R/C, sub, back L & R, side L & R (true side channel sound and not Samsung's meaning). Things get crazy after that: 9.2, 5.2.4, 11.2.2, etc.
