Thank you for your inquiry. The TH46PZ80U has a the AI feature which
equalizes overall volume levels across all channels and external inputs.
We hope this information is helpful to you.
Panasonic Consumer Support
Well, I e-mailed them & directly asked basically the same question as I did here, and that is the response they came back with.
I don't mean to make a huge issue out of it, but they could do a much better job of explaining these features & exactly how they operate. At this point, it sounds to me like the AI feature *should* handle volume equalization for all instances, and the Auto Volume feature somehow applies to external devices only.
Unless of course you are using an OTA antenna with the built-in tuner, every source of input would be considered "external" --- including digital cable boxes hooked up via HDMI. Or at least that's the way to sounds to me, and perhaps more importantly, that is the way it seemed to function on the PX75U set that I briefly had. No matter how I adjusted those features on that set, I had large volume spikes with it.
FWIW, I had a Samsung LCD sitting right next to the Panasonic for a few days, and the volume leveler on that set seemed to work fine with the cable box - as it does on several LG & even Insigna brand sets.
So, this is really a trivial issue when you get right down to it - after all, PQ is what really matters and I would imagine that is the primary reason people would buy these (panasonic) TVs in the first place.
Still, these features should be available on mid line products such as these, and they ought to work the way they are supposed to.
Maybe I was doing something wrong, and if so I want to know what that might be, because I like to know what I'm paying for and I want to know what to expect before I purchase another one of these TVs, which is the reason why I bring it up in this thread since I am most interested in one of these new PZ80 or PZ85 models.