2 Channel stereo, plus a centre?

Blokes,

I've been wondering for a while about the effect of adding a centre speaker to a purely 2 channel music system. Anyone given it a try?

The other day I picked up a nice new centre speaker, so tonight I've hooked it up as shown in the pic below. The system is purely 2 channel, music only.
Source is CD (or stream).
Preamp is digital only.
One digi output feeds a DAC and on to the 2 channel amp, then to the main speakers.
A second SPDI/F output feeds a TC Electronic BMC-2. In this setup it takes the stereo digital signal in, and gives a sum and difference output over SPDI/F to the DSP centre speaker.

I've not found out conclusively, but I believe this is essentially how 'Trifield' processing works.

So, after a few CD's, I think there's some merit in doing some more experimentation. The soundstage is definitely different. Different good or different bad I'm not sure!

Has anyone here had any 'Trifield' or other 3 channel experience?

Cheers,
Jason.