Re: Hello--just bought Sierra L/R/C last night
generally, the best location for a center channel speaker is as close to on-plane with your left/right speakers. this usually puts the center channel below the tv.
my 340SE center is too tall to simply sit in front of my tv on it's stand alone, so it would probably be the same case with yours. i've been trying to decide whether i want to build some sort of platform for the tv to sit on above the center speaker, or just put up some sort of shelf above the tv for the speaker to sit on... my laziness and undecisiveness has been getting the best of me for about 6 months now, leaving me without a dedicated center channel speaker.
CMT-340SE2 Mains & Center, CBM-170SE Surrounds, Rythmik F15, Emotiva XMC-1, Emotiva XPA-5