That sounds like a very shallow filter - that's just over four octaves from 120 to 1000Hz, isn't it?
Regardless of that, it's nothing like the kind of bass signal that is normally in the .1 channel. Also, why would keys be in there too?
Yes, 4.5 octaves or so. Assuming a 12 dB/octave roll off starting at 120Hz, the output should be down by something like 54dB. Probably audible, but considerably lower in level, which is why I asked about the level. Maybe in some cases they simply process the LFE information without roll off or with something very shallow like you mentioned. At 6 dB/octave the signal is only down 27dB. But even so I would expect an LFE channel to begin rolling off lower than 120Hz. Its supposed to be for low frequency augmentation, not a substitute for bass management.
Actually I believe the lowest note on a piano goes down to under 30Hz. So why not keys? I would tend to think that in the case of music the low bass output of all information might get funneled to the LFE channel. Maybe for movie sound it is different, as they may just use the LFE for low frequency effects.
This is probably a good question for the "Ask Steven Wilson" thread.