tried steup to manuals directions but doesn't show for tv systems, all i get is loud noise like a siren. can anyone help please?  i set it up to my pc and it works great except that i still get that incredibly loud siren noise when i  mute the system , so loud that i have to shut the power off. that is the only way it stops.

hmmm. the GMX A-2.1 should be able to receive any line level signal.

For troubleshooting, if you haven't already hooked it up to an alternate source, like a laptop headphone jack or CD player, check that out.

Whether it's working OK (or not) with another source that's helpful information.

It certainly should work with a line level output on the cable receiver/DVD.

Hope you can get it running OK, but if not, Klipsch Tech support is excellent.

That little GMX A-2.1 is a killer system. You will certainly enjoy the results when everything behaves as appropriate.