Originally Posted by krabapple
Sivadselim's post was the first I'd ever heard that claimed no universal player will reroute LFE to mains. It may well be true, but with things like 'Downmix Mode' in existence for years, in even the earliest multichannel DVD players I owned, I don't see why Dolby would mandate discarding LFE in all
cases where sub=NO.
I have been pointing this out for several years, now, and no one has been able to refute it. Many people have scurried off to confirm this only to find out that, unfortunately, their universal player is dropping the LFE channel. But that doesn't mean that ALL universal players drop the LFE channel. I have yet to hear of one that doesn't. I suspect that there may be some very high-end players that treat the LFE channel differently. But it is simple enough to test what a particular player does if you have access to a track that you KNOW is specifically encoded in the LFE channel and LFE channel only. With AVIA this would be the LFE tone that is used for the subwoofer in the speaker channel identification track as well as the "Low Frequency Sweep; LFE" track, which is the best track to use. If you set the SUB=NO and cannot hear the LFE channel-encoded material coming from the front speakers, then it is not being rerouted. But be aware that the subwoofer calibration tracks on AVIA are NOT encoded in the LFE channel, and instead are simply encoded in the main channels and intended to be bass-managed. So, the subwoofer calibration tones are NOT at all useful for verifying what happens to the LFE channel.
As far as I know, if you set a universal player up as SUB=NO, no matter how many main channels you are using, the LFE channel will be dropped. I do not know what a specific "Downmix" mode does, but I suspect it will do the same thing that a standard 2-channel DVD player would do when it plays back a 5.1 soundtrack and passes it via its analog outputs; drop the LFE channel. How 2-channel players treat multichannel (i.e. 5.1 material) content is different than the way that a universal player treats such content. My experience with 2 universal players' analog outs and DVD-A playback has been that, without a downmix mode used, when the player is setup as having only 2 front speakers, upon playback of a 5.1 DVD-A soundtrack, only the front 2 channels are reproduced. The other main channels of the 5.1 soundtrack are simply not reproduced. I assume that the same would apply to DD/DTS5.1 soundtracks. So, that is why a specific "downmix mode" is necessary.
Some universal players have a separate pair of R/L-only analog outs which are completely separate from the multichannel analog output cluster and are not affected by any of the channel settings that apply to the multichannel analog outs. These outputs will behave identically to those of a standard 2-channel DVD player and multichannel content is automatically downmixed and the LFE channel is dropped. However, many players have these 2 separate R/L outputs yet they are NOT treated independently of the front L/R channels of the multichannel analog output cluster. Instead, any settings, such as bass management, that are applied to the front R/L channels of the multichannel cluster are also applied to these 2 R/L-only outputs. So, you have to check what your particular player does with these 2 outputs.
Realize that with most movie soundtracks much of what is mixed into the LFE channel will also be mixed, at least in some measure, into the main channels, as well. So, all is not lost when the LFE channel is dropped. I have heard plenty of 2-channel systems with 2-channel-only analog connections that produced quite a bit of low-end energy.
With multichannel SACD and DVD-A passed via multichannel analog connections, though, and SUB=NO, I suspect the lack of an LFE channel MAY be more noticeable as in most cases, unless a soundtrack is specifically recorded for multichannel playback, the LFE channel is derived from the 2 original stereo tracks and placed into the LFE channel. Of course, for a 2-channel-only setup, almost all SACDs and most DVD-As have a specifically encoded 2-channel track that will contain all of the material that is intended to be heard, so this is not an issue.
Likewise, some (fewer than you realize) DVD movies will also include a specifically-mixed 2-channel track that MAY contain some of the low-end material that would have otherwise been encoded specifically into the LFE track in the multichannel soundtrack. Or, these stereo tracks could simply contain very similar content to what would be reproduced in 2-channel by a player when it downmixes a 5.1 mix for 2-channel analog output. Either way, what is encoded into a specifically-mixed 2-channel DVD movie soundtrack should be expected to contain exactly what an engineer intended it to contain and should provide for satisfactory 2-channel experience.
If you do a search, you will find that there have been efforts (apparently successful) at properly rerouting and merging a universal player's subwoofer channel output back into the front L/R channels using Y-adapters and attenuators. This allows one to leave the player setup as SUB=YES so that the LFE channel is preserved.
Also, as I pointed out, many people have used their universal player with analog connections, setup as SUB=NO, in a multichannel system, and never even realized that their LFE channel was missing.
How 2-channel analog players treat multichannel (i.e. 5.1 material) content is different than the way that a universal player treats such content. My experience with 2 universal players' analog outs and DVD-A playback has been that, without a downmix mode used, when the player is setup as having only 2 front speakers, upon playback, only the front 2 channels are reproduced