Thats the thing though. There have been a few people that claim they couldn't hear it on a high end audio system while there are a few others that claim that they could hear it from things like the speakers from a cheapo 13" tv? According to several, its like when you hear a person make the s sound, its kind of hissy (there have been different descriptions of it). Nbc nightly news seems to be one of the shows that always has it. Here is a recording of it
http://www.mediafire.com/?yuvynylztuv
At least one person said that they didn't notice it till they listened to the recording and knew what they were looking for (I cannot hear it from mine through the computer or the stereo even though I hear it in the recording). I'm guessing that it might be only young people and those rare few older people with very good high frequency hearing (and or those that are sensitive to high frequency noise like a person that cringes when a chalk board squeals). After all, you start loosing your hearing for very high frequency's at rather young ages. these boxes use high frequency noise that supposedly only teenagers can hear (though a few older people can supposedly hear it too).
http://www.boingboing.net/2008/04/23...iseweapon.html

If you want the zenith and have time left on your coupons though, just look for and or wait for a unit that has an April or later manufacture date (as the problem is supposed to be fixed according to user reports). There are already units available in some stores with those dates but not in all stores. If you have a lot of time left, you could wait for other units to come out and see how good they turn out to be, but of what is available right now, the zenith seems to be among the top for quality and capture strength. Of course none of the boxes out yet are perfect (they all have strong and weak points). I would like one with s video out but there are not any good ones yet (not near as good as the zenith).

Here is a comparison chart by the way, for those that want or need certain capabilities.
http://en.wikipedia.org/wiki/Comparison_of_CECB_units