many reviewer note the problem with the led go out but do not go into too much depth about the importance of the led , which make the decision to buy this product somewhat of a risk for I . therefore , I would like to focus my review on that aspect of the product . I have have my 510 for about 2 week now and have mostly love it . the led work flawlessly for I -lrb- so far -rrb- , but what be they really for ? what be the big deal with whether or not the light work ? okay ... there be 2 area of the light ; one area -lrb- on top -rrb- that tell you what `` audio mode '' you be in , and a second area that tell you volume and balance -lrb- whether bass be high\/low , whether the center channel be louder relative to the rear , etc -rrb- . the light on top tell you what signal you have . if you receive a dolby signal , the light on the leave -- directly underneath the DTS\/Dolby logo -- will come on and it will be blue . in the user manual , this light be refer to as be `` position 1 '' . if you receive a dt signal , the light under the DTS\/Dolby logo will be orange . if you do not receive a Dolby or DTS signal , that light just will not be on . I would imagine that if you do not have that light on , it would be annoying because you would not know -lrb- unless you have get the ear of a bat -rrb- for sure whether you be get a true hd signal . however , I do not have animalistic ear so I pretty much rely on that light to tell I whether I have get hd audio . the great thing about this setup though be that even without the Dolby\/DTS , the sound be fantastic . that be where sr come in , which basically simulate surround sound . you have 3 different version of SRS , each of which have very specific function . first there be sr truvolume , which be suppose to maintain consistent volume level when , for instance , change channel . you know how the volume for a tv show will be comfortable , but then the volume in the commercial blast you off the couch ? SRS TruVolume be suppose to prevent that . -lrb- for the record , I do not watch much tv and when I do I just use the tv speaker at a low level anyway , so I can not write on the efficiency of the TruVolume feature -rrb- . you 'll know if you have truvolume on when the Blue light come on right below the SRS logo -lrb- which Vizio refer to as `` position 3 '' -rrb- . next there be the SRS TruSurround feature , which will simulate a hd surround sound even if there be not a true hd audio source . here be what I love about this system , and why I probably would not care if the light fail . even though I do not have the most sensitive ear , I can tell a significant improvement in surround sound quality when the SRS TruSurround be turn on . you hit the SRS tshd button on you slide-out remote and you have get instant hd audio . if you light be work however , you 'll know you have this feature when the light in position 2 -lrb- in between the Dolby and SRS logo -rrb- turn blue . finally with sr , you have SRS WOW HD which be mainly for listen to music . currently I be listen to a fairly rock KT Tunstall track through these speaker and it sound like she be put on a show right in my house -- it be truly that clear . do a blind test -lrb- ie : if the light be not on -rrb- you can still figure out which setting -lrb- off , TruSurround , or WOW HD -rrb- be turn on . when off , the music sound flat . when Tru Surround be on , the music pretty much only come out of the front channel speaker and the instrument get drown out by the vocal . with WOW HD , it sound like a live concert setup ; it just sound natural be the best way I can describe it -- it be perfectly balance . the next set of light come from behind the soundbar foam -lrb- or whatever the technical term for the fabric that cover speaker be call -rrb- . if all volume and balance setting be factory default , you 'll have something that look like this : '' o -rrb- '' . if you turn up the volume , it 'll look like : '' o '' and so on and so forth . you can also adjust the bass , treble , sub , center , and rear channel . if you want more sound from the center channel , hit the right button and you 'll end up with something that look like : '' o '' . or if you want less from the center , '' o '' . when it be even , it 'll look like '' -lrb- o -rrb- '' . these light be probably more important than the orange and blue led because the change be much more subtle -- except for the volume level , which be quite noticeable . have these light work will let you know exactly where the level be . however , even with the light let I know where the level be , I still rely more on my own hearing to figure out where I want the sound to be . when I hit the up\/down button enough to where it sound good to I , I stop . the light indicator be nice and I hope mine do not quit , but it will not upset I too much if they fail . all in all , I be very impressed with the quality of these speaker . whether I be watch a blu-ray disc , a movie on Netflix or Amazon VOD , and whether I have a true-hd -lrb- Dolby or DTS -rrb- source , I feel like I be in the middle of the shot . everything sound crystal clear , from all speaker channel . the only negative about this setup be the lack of additional input . otherwise , it be nearly perfect .