- Panasonic UB820 4K blu ray player (and other digital sources) connected via HDMI to LG CX TV
What type of content do you play through this sources? Mainly multi-channel programme material?
Are you interested in adding 3 more speakers to your room and a far more complicated setup?
If the answer to these question is no then just stick with your setup.
Correct me if I'm wrong but does the down-mixing not include LFE? it's basically just low end frequencies that usually are sent to Sub out, you could still send those to you sub out via Wiim or your active KEF's I would think.
Short version:
It depends. The WiiM Ultra
should preserve the LFE when fed the multi-channel signal through HDMI ARC. If the UB820 is used to downmix a stereo signal to the CX TV or if the CX TV performs the downmix, then the LFE is probably
not included.
Long version:
This is one tricky topic. The LFE channel is
not really "the subwoofer channel", there's no such thing.
The LFE - as the name implies - contains (additional) low frequency effects, only, augmenting the original audio (which
does contains bass information).
Right from the link you posted, here's an excerpt from Dolby's 5.1-Channel Production Guidelines:
What is the difference between the LFE channel and the subwoofer signal? The LFE channel is a separate, limited frequency bandwidth signal created by the mixing engineer and delivered alongside the main channels in the mix.
In professional theatres this content
is reproduced by subwoofers, but that doesn't have to be the case. The content of the LFE channel
can actually be rerouted to regular speakers. The interesting question is how and when that happens
Next paragraph:
The subwoofer signal is created in the decoder as needed for the particular speaker complement in use, using crossover filters. This signal is created using bass management, and all Dolby Digital decoders perform this function. Through bass management, a subwoofer signal may comprise bass from any channel or combination of channels - typically bass frequencies from channels being replayed on small speakers are directed to the subwoofer speaker.
This doesn't really describe how the LFE is handled, but the opposite: How bass information from all channels (including the LFE) can be send to the subwoofer. This does furhter explain how the LFE channel and the subwoofer signal are different, though.
Here's another snippet:
Another benefit to using the LFE channel when carrying explosive bass signals is that smaller stereo systems may not be able to handle such high levels of deep bass without significant stress. Since the Dolby Digital downmix process discards the LFE signal, these low-frequency signals will not present any difficulty for these smaller systems. The remaining portions of the bass frequencies delivered by the main channels will convey the essential aspects of the performance when listening to the downmix.
Many people - explicitely including myself - have always read this like Dolby sepcs would
require the LFE to be dropped from any downmix to 2-channel audio. But, it's a long known fact that many processors
don't do this. According to the experts this was just Dolby's sloppy wording. What they've been really referring to was the way their very own Dolby Digital decoder (a hardware product used e.g. in DVD players) did it. So, when a multi-channel signal is fed into any other processor there's no reason to assume that the LFE would be dropped, at all.
Finally,
here is what
@WiiM Support stated on this topic regarding the WiiM Ultra and the WiiM Amp Pro:
Both products support Dolby Audio and will downmix 5.1 audio to 2.1 when using a single device. We are developing a feature to output satellite channels to separate speakers, effectively creating a 4.1 system when the devices are grouped together.
This is a little sloppy as well, as it seems to imply that the .1 LFE might be routed to the subwoofer output, only. As noted above, there's no need to do so. I take from this that the WiiM Ultra does include the LFE when creating the output signal. Official confirmation would be nice, of course.
