I have the same experience. I have a big center speaker (Kef 204c) and two Verities parsifals for stereo and any unsuspecting listener would swear the vocals come from the center channel when I am playing 2 channel.
However, discrete multi channel is a different story. Because the dialog in movies is mixed to a discrete center channel, if you play native 5.1 on a 4.1 system a DSP needs to send the center channel info to L/R. These L/R channels then need to re-create the center channel image. I never tried 4.1, but I suspect there is come compromise involved.
On the other hand, a big advantage of 4.1 is there is no issue with timbre matching if you have different mains and center speakers/amps (as most people do).
Final consideration against 4.1 is if you prefer playing 5.1 SACD material in DSD source direct mode (like I do), bypassing conversion to PCM and the DSP. If you do this, you cannot play source direct with a 4.1 system because you would loose the center channel information.
However, discrete multi channel is a different story. Because the dialog in movies is mixed to a discrete center channel, if you play native 5.1 on a 4.1 system a DSP needs to send the center channel info to L/R. These L/R channels then need to re-create the center channel image. I never tried 4.1, but I suspect there is come compromise involved.
On the other hand, a big advantage of 4.1 is there is no issue with timbre matching if you have different mains and center speakers/amps (as most people do).
Final consideration against 4.1 is if you prefer playing 5.1 SACD material in DSD source direct mode (like I do), bypassing conversion to PCM and the DSP. If you do this, you cannot play source direct with a 4.1 system because you would loose the center channel information.