Just grab an entry level AV receiver which works with 5.1 speakers & sub. You choose the brand- most would suffice. More important though is, how are you connecting sound to this new component(?) Audio output from the LG HDTV, I presume(?) If so, you will need to make sure your LG model has digital audio output via digital optical. The AV receiver you choose will have to be able to handle digital optical input from the HDTV, unless you have a satellite or cable box somewhere else in your mix that you failed to mention <ahem>.