I have had great success adding a center speaker for improving stereo.
My system is for audio only and uses three identical speakers for LCR, with each speaker having the same subwoofer.
Feeds for LCR come from a matrix processor that can implement matrices such as shown by Elias Pekonen http://elias.altervista.org/html/3_speaker_matrix.html
All forms of LCR matices I've seen so far, use some degree of subtraction L&R from one another, for deriving the new left and the new Right.
And use some degree of L&R addition for deriving the Center.
Which type of chosen matrix works best on any given track, is pure listen and see ime. My processor allows switching between how many I'm willing to load into it.
That said, if I had to choose one matrix, it would probably be one of a energy preserving Gerzon-type implementation.
I've only looked at Gerzon's older work that was meant for audio rooms, but i've seen he put out a paper in 1990 about 3-channel more specifically for home-theatre http://www.audiosignal.co.uk/Resources/Three_channels_USL.pdf
Anyway...what does my LCR rig bring to the party over stereo?
Well, let me first say, I judge audio quality by what I hear outdoors. Either mono or stereo, but most often mono for ease of setup.
The clarity/detail/timbre of outdoors greatly exceeds anything I've heard indoors.
BUT, of course it lacks the room envelopment of indoors.
So, envelopment is gained indoors, but at expense of clarity......particularly with regard to stereo's phantom center, which seldom comes even close to outdoor clarity, ime.
Hence my goal with 3-speaker indoor LCR...get back outdoor clarity and have envelopment too.
It plain works ime....greatly improved center image, and still with envelopment too. Various matrices can trade one attribute for the other.
It's the most enjoyable, clearest indoor sound I've heard yet.
The biggest caveat ime, is that songs really react differently to it; and as said, to particular matrices that make the tradeoff described.
Sometimes, plain ole stereo can't really be improved on. Unfortunately, not often enough imo.
Shows me just how very differently tracks are mastered and there's no such thing as one shoe fits all.
My system is for audio only and uses three identical speakers for LCR, with each speaker having the same subwoofer.
Feeds for LCR come from a matrix processor that can implement matrices such as shown by Elias Pekonen http://elias.altervista.org/html/3_speaker_matrix.html
All forms of LCR matices I've seen so far, use some degree of subtraction L&R from one another, for deriving the new left and the new Right.
And use some degree of L&R addition for deriving the Center.
Which type of chosen matrix works best on any given track, is pure listen and see ime. My processor allows switching between how many I'm willing to load into it.
That said, if I had to choose one matrix, it would probably be one of a energy preserving Gerzon-type implementation.
I've only looked at Gerzon's older work that was meant for audio rooms, but i've seen he put out a paper in 1990 about 3-channel more specifically for home-theatre http://www.audiosignal.co.uk/Resources/Three_channels_USL.pdf
Anyway...what does my LCR rig bring to the party over stereo?
Well, let me first say, I judge audio quality by what I hear outdoors. Either mono or stereo, but most often mono for ease of setup.
The clarity/detail/timbre of outdoors greatly exceeds anything I've heard indoors.
BUT, of course it lacks the room envelopment of indoors.
So, envelopment is gained indoors, but at expense of clarity......particularly with regard to stereo's phantom center, which seldom comes even close to outdoor clarity, ime.
Hence my goal with 3-speaker indoor LCR...get back outdoor clarity and have envelopment too.
It plain works ime....greatly improved center image, and still with envelopment too. Various matrices can trade one attribute for the other.
It's the most enjoyable, clearest indoor sound I've heard yet.
The biggest caveat ime, is that songs really react differently to it; and as said, to particular matrices that make the tradeoff described.
Sometimes, plain ole stereo can't really be improved on. Unfortunately, not often enough imo.
Shows me just how very differently tracks are mastered and there's no such thing as one shoe fits all.