I had the Sophia 2s and preferred using them with the grills on...seemed to have a modest...very modest impact at taming the somewhat hot high end to make them more musical...I suspect, pure guess on my part, that they were designed to have the grills on...can't spectulate on the 7s or 8s...but I suspect the same would be true on the 8s given the more thoughtful grill system...
John
John