[vorbis-dev] Calling for 5.1 Mastering experience! (vorbis ambisonics and 5.1)

[Dave Mercier]

>So, what I'm looking for is some guidance about how the LFE is normally
>and best used in 5.1 mastering. If I had an infinite supply of perfectly
>flat really loud full spectrum speakers and I was setting up an ideal 5.1
>setup, would I mix my LFE into my five speakers, or would I grap another
>one of those perfect speakers and lay it in the corner with the LFE feed
>going into it?

I can't advise too much from a sound design stand point, but I do have a 
fair amount of experience with this on the technology side.

>From what I can tell, the LFE channel is a completely retarded invention. In 
speaking with members of the industry who do 5.1 as a business, they seem to 
think it's retarded too.

In your case you would be better off with 5 full spectrum speakers. I think 
the only possible disadvantage would be that low bass coming from 5 speakers 
where you are not sitting in the sweet spot might have them all arriving out 
of phase and muddying your perception. Of course with all the bass coming 
out of the LFE, it can then be out of phase with the other 5 speakers. But 
if it's just high frequency content coming out of the other 5 speakers, it 
probably won't get as muddy as the low bass would.

The following things make the LFE channel stupid:

1) In a standard fold-down, If the 5.1 signal is down mixed to anything 
lower like PLII, stereo, etc., the signal in the LFE channel is completely 
thrown away. So you must not put anything in the signal that is important. 
You can only put stuff in there that's not important. So I start to ask 
what's the point?
2) All receivers perform bass management. If you have pathetic small 
speakers and a kicking subwoofer, your receiver will implement a cross-over 
for you and filter all the bass content out of all channels and send it just 
to the subwoofer. If you have full range speakers it may not send anything 
to the sub woofer and leave the bass content in the mains. So the .1 channel 
is basically emulated half the time anyway.

How this all fits into Ambisonics I no know. You might have to follow along 
and have a .1 channel anyway. I know the .1 channels makes other things hard 
as well, I wish the industry would just dump it (lets go for 8.0 or 10.0 
next, not 7.1 or 8.2!).

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