How does headphone spatialization work?

[koroptev]

First - where do I have to set it and how are these settings related to each other. I found 3 places that relate to something like "compute 2 channels from all available for headphones", these are:
1.) Tools/Preferences/Audio (show settings - simple)/Headphone surround effect
2.) Tools/Preferences/Audio (show settings - simple)/Dolby surround
3.) Tools/Preferences/Audio (show settings - all)/Filters/Headphone virtual spatialization effect
Option 2.) is probably unrelated unless I want to "might enhance my experience in combination with headphone channel mixer". Options 1.) & 3.) can be both selected independently, so they're not lookin like the same option in just different type of interface (simple/all). So - what does what, what are my options and what it does when I pick them when using headphones?
Next question - and I've found this one unanswered here - when I selected option 3.) (which is what I trused the most) and feeded VLC with multichannel sound input, I definitely got different outputs in my ears depending on whether I picked during playback (right mouse)/sound/sound device/5.1 or left preselected sound device/stereo. Depending on input one option gives better output than the other, but I'd like to know, what happens behind - whether I'm just directly listening to 2 channels in case of one option and computed result in case of other or what.
Thanks.

[VLC_help]

http://mailman.videolan.org/pipermail/v ... 61729.html simple preferences option might be still broken.

Downmixing will be different if you select 5.1 instead of stereo. With stereo there are at least two mixing setups, but with 5.1 it is only one (assuming that you play 5.1 audio).

[koroptev]

ok, so 1.) = 3.), but what do you mean by "at least two mixing setups"? My source is 5.1, i check 3.), what should i select - 5.1 device or stereo, which does what?

[koroptev]

it's nice this app has feature nobody knows how to use or how it works, at least another checkbox to play with..

[VLC_help]

There isn't any right option since there isn't any absolute standard for downmixing 5.1 -> stereo. So use one that you like.

[koroptev]

but I don't even know whether there's some donwmixing happenning - what if I'm simply getting 2 of those 6 channels into my ears when I select 5.1 device (even if spatialization checked; it's output device if I understand that option correctly)? I don't say it's that way, because I don't know, but then - your answer didn't deny nor support this..

[VLC_help]

what if I'm simply getting 2 of those 6 channels into my ears when I select 5.1 device

That would be easy to spot. You wouldn't hear dialog/voices at all since they are in center channel.

[koroptev]

ok, thanks for that info; so basicaly it's about what suits more, because some downmixing always happens

[Qwintillion]

Apparently VLC help is for either idiots or experts and no in-between. I've tried to find out how headphone spatialization works for over 45 minutes and I still don't know, so apparently I'm an idiot and I have searched in vain.