Well, as Scandy says, the original firmwares seemed to apply a different channel weighting when they did the downmix, which most users prefer.
As I said, the volume _ IS _ low and the mix ends up with low dialogue and high BGM and effects. But it’s that way on the original disc when I try with 3 different stand-alones, and the WDTV levels are not apparently any different. Before my WDTV I had to watch any DVDs that didn’t have a 2.0 track, at night, with the subtitles on because if they were quiet enough that the music and effects didn’t bother my family trying to sleep, then I couldn’t hear the dialogue at all. And I’ve always had to crank the TV’s volume if I’m playing back DVDs, whether a 5.1 track or a 2.0 track.
But, my point about “dismissing”, was that in the past when I tried to point out that all AC3 plays like this for me, even on the original disc (like in the comments of the post you linked to – container was irrelevant, all downmixed AC3 was just quiet, both 2.0 and 5.1), you had said that was not the case, and that for you AC3 in vobs was significantly lower than the original disc and lower than AC3 in other containers, such as .mkv and .avi – you said the issue you were complaining about was strictly limited to 5.1 AC3 pulled out of vobs, and was not an issue with the 5.1 channel weightings.
So, that was what I just re-tested yesterday. For me, there is no change, whether its the original disc, an MKV or a vob.
All 3 (including the original disc) are considerably lower than other audio streams, but I can’t notice vobs being any lower than other containers or the original audio stream – as I said, if anything, they’re a tad higher, but not significantly so. And that post you linked to is also talking of all AC3 being too low, and not vobs being significantly lower than other containers, so it doesn’t seem to be describing your reported problem at all.
For all I know, it was Dolby Labs that made WD change the channel weightings for the downmix, in order to maintain the DD licencing. I have no clue why it was changed. All I know is that since the change, the WDTV sounds exactly like the original disc, when played from every player I have access to, in terms of both levels and mix of channels. So, even though I’d like a better mix, with more emphasis on dialogue, and less on gunshots, I’m not convinced the current mix can be called a “bug”.
I must also add, that of all the people that are complaining about the AC3 5.1 downmix, and low dialogue levels, I’ve not seen any others say that it is lower than the audio on the original DVD, or that vobs are quieter than AC3 in other containers.