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Sly
Premium
join:2004-02-20
Chuckey, TN
kudos:2
Reviews:
·Callcentric

Want to upconvert 5.1 to 7.1 surround...

I'm running a Windows 7 home theater PC to power my theater and would like to use the full 7.1 capabilities of my soundcard. I have a creative labs X-Fi Fatal1ty 7.1 soundcard hooked up to a 7 channel system with subwoofer.

Basically there is no real 7.1 content. The soundcard works great for games and upmixing music with EAX effects but unless I want to watch the same few Blurays over and over, there is nothing encoded in 7.1 sound. Even most newer movies are back to 5.1...

I want to listen to 7.1 surround all the time even when playing 5.1 content but I don't want the side channels to be just a copy of the rear speakers nor do I want to add EAX to the movie I'm watching.

What I would like is a real time plugin that would create side channel sound. What I'm thinking is that as a sound pans from front to rear, a phantom side channel is created. If you take the front channel audio and subtract it from the rear channel audio you would effectively eliminate the center audio (audio that was common to front and rear would be eliminated through phase cancellation). Then I would like to then flip it so that the remainder of the track (which would be the sounds that are not unique to the front or rear) would then be deleted and the center material would then be added back.

What you would end up with would be a sound that would start in the front, pan through the side and then end up in the rear channel. I want to create an actual side channel signal instead of having a phantom side channel by using simple phase cancellation techniques.

There are some realtime VST plugins that delete the center channel material from 2 channel music. They do this to remove the vocals which are usually common to both channels in mono. If you subtract the left channel from the right channel you will delete the center channel material because what was common to both speakers would cancel out due to the 180* phase shift. I want to apply this technique to creating a side channel but instead of deleting the phantom center side sounds, I want to play only the center side sounds while eliminating the front and rear channels.

Any ideas? Anything out there that does this?


Sly
Premium
join:2004-02-20
Chuckey, TN
kudos:2
Reviews:
·Callcentric
So far the best solution I've found is AC3 Filter.




They have matrix mixing whereby you can switch channel assignments and combine channels together. So far I've created a side channel by adding some of the front and some of the rear. This will include the mono signal of the two but unfortunately it will also include the discrete portion of the audio as well. I still haven't found a way to exclude the sound that is exclusive for the front/rear channels. If you place a -1 in the matrix, it will play that channel out of phase. If I do this then the front and rear will cancel each other out in the side channel and I will lose the mono signal and be stuck with only the discrete portion of the audio.

Still looking for a way to cancel out the discrete sounds, leaving only the mono... But for now this seems to work well in that at least I have a side channel that plays and helps to fill in the room as the sounds pan from front to back.


IllIlIlllIll
EliteData
Premium
join:2003-07-06
Hampton Bays, NY
kudos:7
this plugin i use on winamp does what you seek, nulls out the left and right (and reverse phase mono of L/R) but keeps mono.
although it will not work for your setup, it does what i want which is to remove left and right but keep mono.
i use this plugin when im playing tunes simply because it makes certain tunes sound "different".
the concept and theory behind the way the plugin operates is the same manner Dolby Pro Logic operates but "stronger".
»code.google.com/p/centercutplus/
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