Jaco,
thats right- technically speaking. I was advised by a Meridian installer to try a negative setting. In my setup it really improved the sound- vocals seem so much more focused. all you have to do is put on some good vocal music and play with the setting until it seems right. I dont get hung up on what the - or + mean, just which produces the best result.

Best regards,
Jerry
Main System: 861v6, DSP8000s in corners, DSP7000s Center and Sides, 1-9 humans.