Kibber or Sibber

Just now I was wondering if the surname Cibber – as in the much-mocked poet Colley Cibber and his sculptor father Caius Gabriel Cibber – was pronounced Kibber or Sibber. As if it mattered.
It's not a name I often have occasion to utter, but as Caius Gabriel features in my book, I thought I'd make sure. So I decided to look online, as the answers to every question live out there in cyberspace. Sure enough, there were websites queuing up to enlighten me on this vital question. The first one I tried nearly made me jump out of my skin. Brace yourself...

I'm not going to forget that in a hurry.