This is a very important question, and I wish I felt more confident about the answer.
I pushed on this here with folks who should be able to test and confirm the answer back around the holidays (I don't have the player to do this myself), and the consensus result was that the D2 and AVM-50 do *NOT* suffer from this problem. But I'm not really sure any of the folks responding actually tested the right thing. They may have, but the folks who responded didn't actually spell it out enough for me to be sure.
If the D2 had the problem I would expect more complaints from the folks who populate this thread, but the comments in other threads make it clear that people can confuse themselves into thinking there is no problem here.
For folks who don't know what we are talking about, see this thread in the Audio Theory forum here:
In short, any receiver or pre/pro that handles multi-channel analog audio input via RCA, or multi-channel PCM input via HDMI, should, by default, boost the LFE input signal by 10dB prior to mixing with any other base signals and output to the subwoofer.
Failure to do this will lead to weak bass when listening to multi-channel analog tracks or multi-channel PCM tracks (as from HD-DVD or Blu-Ray players). To fulfill its role as a channel for recording *LOUD* bass (explosions and stuff), the LFE channel is deliberately recorded 10dB low so as to avoid clipping in processing and transmission prior to output. This is by design. It is not a mistake in the audio track or a bug in the player. It is the job of the receiver or pre-pro to boost LFE to get it back to where it is supposed to be prior to output. LFE for Dolby Digital and DTS has worked this way for years.
Boosting total subwoofer output in the receiver or pre-pro is not a proper fix for this since that also incorrectly boosts bass steered to the subwoofer from the main speakers.
The LFE boosting also happens when standard Dolby Digital or DTS is decoded in the receiver or pre/pro, but since that's such a commodity technology EVERYBODY gets that right. The only issue is with LFE on multi-channel analog or multi-channel PCM input.
There ARE a few odd-ball cases where the LFE boost is INCORRECT (see the cited thread), and thus the receiver or pre/pro needs a feature for the user to temporarily *CUT* LFE by 10dB. The D2 and AVM-50 do have that feature -- a temporary cut of JUST the LFE available as a second press under the Subwoofer key on the remote. However that feature only allows LFE to be cut, so it can't be used to boost just LFE to fix the bug at issue here if the D2 or AVM-50 actually have that bug.
The test of whether the D2 or AVM-50 have the bug involves playing the same track via multi-channel PCM over HDMI and also as the compatibility "bitstream" track over HDMI or (optical/coax digital audio cabling) that gets decoded in the D2 as an incoming DTS track. If the D2 or AVM-50 has the bug, bass in the PCM version will be significantly weaker. The effect is not subtle. For correct operation, bass in the two tracks needn't be completely identical, but if the bug is in there the PCM version will be noticeably anemic.